Learn by Novus · Open practice pack v1

Coding and decoding: full practice bank: open practice pack: learner worksheet

100 untimed questions across 10 authored sections.

This is untimed educational practice for one cognitive skill. It is not a clinical, diagnostic, employment, or professionally recognized assessment, and it does not produce an IQ score or credential.

Learner worksheet

Coding and decoding is the skill of spotting the rule that turns a word into a code, then applying it in reverse. One hundred items in ten themed sections, each one self-contained: every rule you need is stated in the question itself. Work untimed and write the alphabet out beside you at first; recognising the common rule families is what builds speed later.

Choose one answer for each item. For a delayed-recall item, read its study text, cover it, and then answer without looking back.

Letter positions and number codes

Warm up with the most common code of all: each letter stands for its place in the alphabet, so A is 1 and Z is 26.

1. coding-decoding-s01-q01

In a code, each letter is replaced by its position in the alphabet, so A is 1 and B is 2. What number stands for the letter G?

  1. 5
  2. 6
  3. 7
  4. 8

Answer:

2. coding-decoding-s01-q02

In a code where A is 1 and Z is 26, which letter is written as the number 12?

  1. K
  2. L
  3. M
  4. N

Answer:

3. coding-decoding-s01-q03

In a code, each letter is replaced by its alphabet position, so CAB is written 3-1-2. How is BAD written?

  1. 2-1-4
  2. 2-1-3
  3. 1-2-4
  4. 4-1-2

Answer:

4. coding-decoding-s01-q04

In a code, DOG is written 4-15-7 because each letter is replaced by its alphabet position. How is COW written?

  1. 3-15-22
  2. 3-14-23
  3. 3-15-23
  4. 3-15-24

Answer:

5. coding-decoding-s01-q05

In a code where each letter is replaced by its alphabet position, which word is written 19-21-14?

  1. SIN
  2. SUN
  3. RUN
  4. SON

Answer:

6. coding-decoding-s01-q06

In a code, letters are replaced by their alphabet positions, so M is written 13. Which letter is written 20?

  1. S
  2. T
  3. U
  4. V

Answer:

7. coding-decoding-s01-q07

In a code, a word is written as the total of its letters' alphabet positions. What number stands for the word CAB?

  1. 6
  2. 7
  3. 8
  4. 9

Answer:

8. coding-decoding-s01-q08

In a code, ACE is written 1-3-5 because each letter is replaced by its alphabet position. Which word is written 2-4-6?

  1. BCF
  2. BDG
  3. ACF
  4. BDF

Answer:

9. coding-decoding-s01-q09

In a code, letters are replaced by their alphabet positions. Which letter has a position number exactly double that of D?

  1. G
  2. H
  3. I
  4. J

Answer:

10. coding-decoding-s01-q10

In a code, TEN is written 20-5-14 because each letter is replaced by its alphabet position. Which word is written 20-5-1?

  1. ATE
  2. EAT
  3. NET
  4. TEA

Answer:

Shifting letters forward and back

Shift codes replace every letter with one a fixed number of places away. Watch what happens at the ends of the alphabet, where counting wraps around.

11. coding-decoding-s02-q01

In a code, every letter is replaced by the letter one place later in the alphabet. How is CAT written?

  1. DBU
  2. BZS
  3. CBU
  4. DAU

Answer:

12. coding-decoding-s02-q02

In a code, every letter is replaced by the letter one place later in the alphabet. How is DOG written?

  1. EOH
  2. EPG
  3. EPH
  4. CNF

Answer:

13. coding-decoding-s02-q03

In a code, every letter is replaced by the letter two places later in the alphabet. How is BAT written?

  1. DCV
  2. CBU
  3. DBV
  4. DCU

Answer:

14. coding-decoding-s02-q04

In a code, every letter is replaced by the letter one place earlier in the alphabet. How is SUN written?

  1. TVO
  2. RTM
  3. RUM
  4. RTN

Answer:

15. coding-decoding-s02-q05

In a code, every letter is replaced by the letter two places earlier in the alphabet. How is FOG written?

  1. EMF
  2. DMF
  3. DNE
  4. DME

Answer:

16. coding-decoding-s02-q06

In a code, PEN is written QFO. Using the same rule, how is CUP written?

  1. DVQ
  2. BTO
  3. DUQ
  4. DVP

Answer:

17. coding-decoding-s02-q07

In a code, TIME is written SHLD. Using the same rule, how is DAY written?

  1. EBZ
  2. CZX
  3. CAX
  4. DZX

Answer:

18. coding-decoding-s02-q08

In a code, every letter is replaced by the letter one place later in the alphabet, and the alphabet is treated as a loop so Z becomes A. How is ZOO written?

  1. YNN
  2. AOO
  3. APP
  4. APO

Answer:

19. coding-decoding-s02-q09

In a code, every letter is replaced by the letter three places later in the alphabet. How is CAB written?

  1. EDC
  2. FDE
  3. FCE
  4. GED

Answer:

20. coding-decoding-s02-q10

A word was coded by moving each of its letters four places later in the alphabet, producing GEX. What was the original word?

  1. BAT
  2. CAT
  3. COT
  4. CAP

Answer:

Reversal and mirror codes

Two related families here: reversing the order of letters, and mirroring the alphabet so A pairs with Z. Decide which one is at work before you answer.

21. coding-decoding-s03-q01

In a code, every word is written with its letters in reverse order. How is DESK written?

  1. SKED
  2. KSDE
  3. EDSK
  4. KSED

Answer:

22. coding-decoding-s03-q02

In a code, LEMON is written NOMEL because the letters are reversed. How is APPLE written?

  1. ELPPA
  2. ELPAP
  3. EPLPA
  4. APPEL

Answer:

23. coding-decoding-s03-q03

In a code, each word of a phrase is reversed but the words stay in their original order. How is OPEN DOOR written?

  1. ROOD NEPO
  2. NEPO DOOR
  3. NEPO ROOD
  4. NOPE ROOD

Answer:

24. coding-decoding-s03-q04

In a code, GO HOME is written EMOH OG because the whole phrase, words included, is written backwards. How is SIT DOWN written?

  1. TIS NWOD
  2. NWOD TIS
  3. TIS DOWN
  4. NWOD SIT

Answer:

25. coding-decoding-s03-q05

In a mirror code, A is written Z, B is written Y, and so on down the alphabet. How is the letter C written?

  1. V
  2. W
  3. X
  4. Y

Answer:

26. coding-decoding-s03-q06

In a mirror code where A is written Z and B is written Y, how is the word CAB written?

  1. XYZ
  2. ZXY
  3. YZX
  4. XZY

Answer:

27. coding-decoding-s03-q07

In a mirror code where A is written Z, B is written Y, and so on, how is the word ZOO written?

  1. AKK
  2. BLL
  3. ALL
  4. ALK

Answer:

28. coding-decoding-s03-q08

In a mirror code where A is written Z, B is written Y, and so on, which word is written TLLW?

  1. FOOD
  2. GOLD
  3. WOOD
  4. GOOD

Answer:

29. coding-decoding-s03-q09

In a code, STOP is written TSPO because the letters are swapped in pairs. How is CARD written?

  1. ACRD
  2. CADR
  3. ACDR
  4. DRAC

Answer:

30. coding-decoding-s03-q10

In a code, HORSE is written ESROH because the letters are reversed. Which word is written TFARC?

  1. FRACT
  2. CRAFT
  3. CARFT
  4. TRACE

Answer:

Rearranged-letter codes

These codes keep every letter but move it somewhere else. Work out exactly which positions travel where before applying the rule.

31. coding-decoding-s04-q01

In a code, DEAR is written EDRA because neighbouring letters are swapped in pairs. How is FISH written?

  1. IFSH
  2. FIHS
  3. HSIF
  4. IFHS

Answer:

32. coding-decoding-s04-q02

In a code, CHAIR is written RHAIC because the first and last letters change places. How is TABLE written?

  1. EABLT
  2. ELBAT
  3. EABTL
  4. TABEL

Answer:

33. coding-decoding-s04-q03

In a code, MONEY is written ONEYM because the first letter moves to the end. How is PAPER written?

  1. REPAP
  2. PAPRE
  3. APERP
  4. APEPR

Answer:

34. coding-decoding-s04-q04

In a code, GARDEN is written NGARDE because the last letter moves to the front. How is PENCIL written?

  1. ENCILP
  2. LICNEP
  3. PENCLI
  4. LPENCI

Answer:

35. coding-decoding-s04-q05

In a code, TIME is written METI because the last two letters move to the front. How is CARD written?

  1. DRAC
  2. RDCA
  3. RDAC
  4. ARCD

Answer:

36. coding-decoding-s04-q06

In a code, the letters of a four-letter word are rewritten in the order second, first, fourth, third. How is LAMP written?

  1. ALMP
  2. LAPM
  3. ALPM
  4. PMAL

Answer:

37. coding-decoding-s04-q07

In a code, BOOK is written OKBO because the first two letters move to the end. How is DESK written?

  1. KSED
  2. SKED
  3. EDKS
  4. SKDE

Answer:

38. coding-decoding-s04-q08

In a code, every word is rewritten with its letters in alphabetical order. How is CHAIR written?

  1. ACHRI
  2. ACHIR
  3. AICHR
  4. RIAHC

Answer:

39. coding-decoding-s04-q09

In a code, the middle letter of a five-letter word is moved to the front and the rest keep their order. How is BRAIN written?

  1. ABRNI
  2. ARBIN
  3. ABRIN
  4. NIARB

Answer:

40. coding-decoding-s04-q10

In a code, a six-letter word is written with its two halves swapped. How is GARDEN written?

  1. NEDRAG
  2. DENGAR
  3. DENRAG
  4. RAGNED

Answer:

Working out the rule from an example

Now the rule is not stated. Compare the example word with its code letter by letter, name the rule, then apply it.

41. coding-decoding-s05-q01

In a code, MOON is written NPPO. Using the same rule, how is STAR written?

  1. SUBS
  2. TUBS
  3. TUAS
  4. RSZQ

Answer:

42. coding-decoding-s05-q02

In a code, HAND is written IBOE. Using the same rule, which word is written CMPX?

  1. GLOW
  2. CLAW
  3. BLOW
  4. BLEW

Answer:

43. coding-decoding-s05-q03

In a code, FLOWER is written GMPXFS. Using the same rule, how is GARDEN written?

  1. HBSDFO
  2. FZQCDM
  3. HBRDFO
  4. HBSEFO

Answer:

44. coding-decoding-s05-q04

In a code, CAT is written 3-1-20. Using the same rule, how is TAP written?

  1. 20-1-15
  2. 20-1-16
  3. 19-1-16
  4. 16-1-20

Answer:

45. coding-decoding-s05-q05

In a code, BOX is written YLC. Using the same rule, how is CAP written?

  1. XAK
  2. ZXK
  3. XZK
  4. XZL

Answer:

46. coding-decoding-s05-q06

In a code, ONE is written 15-14-5 and TWO is written 20-23-15. Using the same rule, how is SIX written?

  1. 19-9-24
  2. 18-9-24
  3. 19-8-24
  4. 19-9-23

Answer:

47. coding-decoding-s05-q07

In a code, a word is written as a single number, and RED is written 27. Using the same rule, how is BED written?

  1. 11
  2. 12
  3. 13
  4. 14

Answer:

48. coding-decoding-s05-q08

In a code, SUN is written TWQ. Using the same rule, how is DAY written?

  1. EBA
  2. ECB
  3. ECA
  4. EDB

Answer:

49. coding-decoding-s05-q09

In a code, FOUR is written EMRN. Using the same rule, how is FIVE written?

  1. EGRA
  2. EHSA
  3. EGSB
  4. EGSA

Answer:

50. coding-decoding-s05-q10

In a code, LAMP is written 12-1-13-16. Using the same rule, which word is written 4-9-19-8?

  1. DASH
  2. DISH
  3. FISH
  4. DISK

Answer:

Coded language: matching words to meanings

Each item gives short phrases in an invented language. Find the code word that appears in more than one phrase, match it to the meaning those phrases share, and work outwards from there.

51. coding-decoding-s06-q01

In a code language, "tor mel" means "red apple" and "mel dik" means "apple pie". Which code word means "apple"?

  1. mel
  2. tor
  3. dik
  4. It cannot be worked out

Answer:

52. coding-decoding-s06-q02

In a code language, "ral fim" means "cold night" and "fim dop" means "night sky". What does "ral" mean?

  1. night
  2. sky
  3. cold
  4. dark

Answer:

53. coding-decoding-s06-q03

In a code language, "mo ta ku" means "sweet mango juice", "ta si" means "mango tree", and "ku ne" means "juice bar". Which code word means "sweet"?

  1. mo
  2. ta
  3. ku
  4. si

Answer:

54. coding-decoding-s06-q04

In a code language, "pen zol" means "green field", "zol fim" means "field mouse", and "fim rak" means "mouse trap". What is the code for "green trap"?

  1. pen zol
  2. zol rak
  3. pen rak
  4. rak fim

Answer:

55. coding-decoding-s06-q05

In a code language, "lo ka mi" means "fast blue train", "ka su" means "blue sea", and "mi te" means "train station". What does "lo" mean?

  1. blue
  2. train
  3. station
  4. fast

Answer:

56. coding-decoding-s06-q06

In a code language, "sun" is "ora", "rises" is "tam", and "early" is "vek". Keeping the same word order, how would "sun rises early" be written?

  1. ora vek tam
  2. tam ora vek
  3. ora tam vek
  4. vek tam ora

Answer:

57. coding-decoding-s06-q07

In a code language, "fa lo mi" means "birds fly south", "mi ru" means "south wind", and "lo pen" means "fly high". Which code word means "birds"?

  1. lo
  2. mi
  3. fa
  4. ru

Answer:

58. coding-decoding-s06-q08

In a code language, "tin ko sa" means "buy fresh bread", "sa lem" means "bread shop", and "ko dor" means "fresh fruit". Which code word means "buy"?

  1. tin
  2. ko
  3. sa
  4. lem

Answer:

59. coding-decoding-s06-q09

In a code language, "ze bo" means "night sky", "bo fa" means "sky blue", and "fa ze" means "blue night". Which code word means "sky"?

  1. ze
  2. bo
  3. fa
  4. It cannot be worked out

Answer:

60. coding-decoding-s06-q10

In a code language, "mek tor sil pa" means "we play games daily", "sil ken" means "games room", "pa nod" means "daily paper", and "tor lim" means "play area". Which code word means "we"?

  1. tor
  2. sil
  3. pa
  4. mek

Answer:

Number and symbol substitutions

Codes that mix letters, digits, and symbols. Convert carefully in one direction at a time, and note whether any arithmetic is applied after the lookup.

61. coding-decoding-s07-q01

In a code, each letter is replaced by a number one more than its alphabet position, so A is written 2. How is CAB written?

  1. 3-1-2
  2. 2-4-3
  3. 4-1-3
  4. 4-2-3

Answer:

62. coding-decoding-s07-q02

In a code, each letter is replaced by double its alphabet position. How is BAD written?

  1. 2-1-4
  2. 4-2-6
  3. 4-2-8
  4. 8-2-4

Answer:

63. coding-decoding-s07-q03

In a code, a word is written as the total of its letters' alphabet positions. What number stands for the word BAG?

  1. 8
  2. 9
  3. 10
  4. 11

Answer:

64. coding-decoding-s07-q04

In a code, the digits are replaced by letters as follows: 1 is P, 2 is Q, 3 is R, 4 is S, and 5 is T. How is the number 3514 written?

  1. RTPS
  2. RPTS
  3. RTSP
  4. PRTS

Answer:

65. coding-decoding-s07-q05

In a code, the digits are replaced by letters as follows: 1 is P, 2 is Q, 3 is R, 4 is S, and 5 is T. Which number is written TQPR?

  1. 5231
  2. 2513
  3. 5123
  4. 5213

Answer:

66. coding-decoding-s07-q06

In a code, each letter is replaced by its alphabet position multiplied by 2, with 1 then subtracted, so A is written 1 and B is written 3. How is DAD written?

  1. 7-1-7
  2. 8-2-8
  3. 7-2-7
  4. 4-1-4

Answer:

67. coding-decoding-s07-q07

In a code, the symbol # stands for A, * stands for E, and @ stands for I, while every other letter is written as usual. How is the word BEAD written?

  1. B#*D
  2. B*@D
  3. B*#D
  4. BE#D

Answer:

68. coding-decoding-s07-q08

In a code, each letter is replaced by the alphabet position of the letter that follows it, so A is written 2. How is CAT written?

  1. 3-1-20
  2. 2-0-19
  3. 4-2-20
  4. 4-2-21

Answer:

69. coding-decoding-s07-q09

In a code, a word is written as the total of its letters' alphabet positions, and SEA is written 25. Which of these words is also written 25?

  1. CAT
  2. TEA
  3. LID
  4. BED

Answer:

70. coding-decoding-s07-q10

In a code, each letter is replaced by the number of the position it holds counting backwards from Z, so Z is written 1 and Y is written 2. How is BAD written?

  1. 2-1-4
  2. 24-26-23
  3. 25-26-24
  4. 25-26-23

Answer:

Conditional coding rules

Here the rule applies only to certain letters or in certain conditions. Sort the letters into the cases first, then code each case correctly.

71. coding-decoding-s08-q01

In a code, every vowel is replaced by the next letter of the alphabet and every consonant is left unchanged. How is TABLE written?

  1. TBBLF
  2. TABLF
  3. TBBLE
  4. UBCMF

Answer:

72. coding-decoding-s08-q02

In a code, every vowel is replaced by the next letter of the alphabet and every consonant is left unchanged. How is MUSIC written?

  1. MVSIC
  2. MUSJC
  3. MVSJC
  4. NVTJD

Answer:

73. coding-decoding-s08-q03

In a code, every consonant is replaced by the letter before it in the alphabet and every vowel is left unchanged. How is FACE written?

  1. EABE
  2. EABD
  3. FBCD
  4. EACE

Answer:

74. coding-decoding-s08-q04

In a code, a word is reversed if it has an even number of letters and left unchanged if it has an odd number. How is the pair HAND and CAT written?

  1. DNAH, TAC
  2. HAND, TAC
  3. DNAH, CAT
  4. HAND, CAT

Answer:

75. coding-decoding-s08-q05

In a code, any letter that appears more than once in a word is replaced by a star wherever it appears, and all other letters stay as they are. How is LETTER written?

  1. L****R
  2. LE**ER
  3. L*TT*R
  4. LETTER

Answer:

76. coding-decoding-s08-q06

In a code, every vowel is replaced by its alphabet position number and every consonant is left unchanged. How is HEAD written?

  1. H5AD
  2. 851D
  3. H15D
  4. H51D

Answer:

77. coding-decoding-s08-q07

In a code, a word is written backwards and the letter S is then added at the end. How is DREAM written?

  1. MAERD
  2. MAERDS
  3. SMAERD
  4. DREAMS

Answer:

78. coding-decoding-s08-q08

In a code, letters in odd positions move one place forward in the alphabet and letters in even positions move one place back. How is CODE written?

  1. DPEF
  2. BPCF
  3. DNED
  4. DNEF

Answer:

79. coding-decoding-s08-q09

In a code, a word that starts with a vowel is reversed, while a word that starts with a consonant has only its first and last letters swapped. How are OPEN and DESK written?

  1. NEPO, KESD
  2. OPEN, KESD
  3. NEPO, DESK
  4. NEPO, KSED

Answer:

80. coding-decoding-s08-q10

In a code, every third letter of a word is dropped and the remaining letters keep their order. How is CALENDAR written?

  1. CALEDA
  2. CAENAR
  3. CAENDR
  4. CAELNR

Answer:

Two-step codes

Each code here applies two operations one after the other. Do them strictly in the order stated, and when decoding, undo them in the opposite order.

81. coding-decoding-s09-q01

In a code, a word is first written backwards and then every letter moves one place forward in the alphabet. How is CAT written?

  1. UBD
  2. DBU
  3. UAD
  4. TAC

Answer:

82. coding-decoding-s09-q02

In a code, every letter first moves one place back in the alphabet and the word is then written backwards. How is DOG written?

  1. CNF
  2. FNC
  3. EPH
  4. HPE

Answer:

83. coding-decoding-s09-q03

In a code, every letter is first replaced by its mirror letter, so A becomes Z and B becomes Y, and the word is then written backwards. How is CAB written?

  1. XZY
  2. BAC
  3. ZYX
  4. YZX

Answer:

84. coding-decoding-s09-q04

In a code, every letter first moves two places forward in the alphabet and the first and last letters of the result are then swapped. How is LAMP written?

  1. RCON
  2. NCOR
  3. ROCN
  4. PMAL

Answer:

85. coding-decoding-s09-q05

In a code, the vowels of a word first move one place forward in the alphabet and the whole word is then written backwards. How is RAIN written?

  1. RBJN
  2. NJBR
  3. NIAR
  4. NJBS

Answer:

86. coding-decoding-s09-q06

In a code, a word is first written backwards and each letter is then replaced by its alphabet position. How is BAD written?

  1. 2-1-4
  2. 4-2-1
  3. 1-4-2
  4. 4-1-2

Answer:

87. coding-decoding-s09-q07

In a code, every letter first moves three places forward in the alphabet and the result is then written backwards. How is BOX written?

  1. ERA
  2. XOB
  3. ARE
  4. AER

Answer:

88. coding-decoding-s09-q08

In a code, the first two letters of a four-letter word are first moved to the end and every letter then moves one place back in the alphabet. How is DESK written?

  1. RJCD
  2. SKDE
  3. CDRJ
  4. RJDC

Answer:

89. coding-decoding-s09-q09

In a code, every vowel is first replaced by its alphabet position number and the whole word is then written backwards. How is FACE written?

  1. F1C5
  2. 5C1F
  3. 5C1E
  4. ECAF

Answer:

90. coding-decoding-s09-q10

A word was coded by moving each letter two places forward in the alphabet and then writing the result backwards, producing RCO. What was the original word?

  1. PAM
  2. MAT
  3. CAP
  4. MAP

Answer:

Breaking codes and advanced patterns

The hardest section: keyword alphabets, grid references, and codes you must break from a single worked example before you can use them.

91. coding-decoding-s10-q01

A code alphabet is built by writing the keyword MUSIC first and then the unused letters in their normal order, giving M, U, S, I, C, A, B, D, E and so on. The plain letter A is coded as the first letter of this new alphabet, B as the second, and so on. How is BAD written?

  1. UMI
  2. MUI
  3. UMS
  4. IMU

Answer:

92. coding-decoding-s10-q02

A code alphabet is built by writing the keyword MUSIC first and then the unused letters in their normal order, giving M, U, S, I, C, A, B, D, E and so on, with the plain letter A coded as the first entry, B as the second, and so on. Which word is written SMU?

  1. ABC
  2. BAC
  3. CBA
  4. CAB

Answer:

93. coding-decoding-s10-q03

In a code, the letters are set out in a five-column grid, row by row: A B C D E, then F G H I J, then K L M N O, then P Q R S T, then U V W X Y, with Z left out. Each letter is written as its row number followed by its column number, so H is 23. How is CAB written?

  1. 11-12-13
  2. 13-11-12
  3. 31-11-21
  4. 13-12-11

Answer:

94. coding-decoding-s10-q04

In a code, the letters are set out in a five-column grid, row by row: A B C D E, then F G H I J, then K L M N O, then P Q R S T, then U V W X Y, with Z left out, and each letter is written as its row number followed by its column number. Which word is written 45-15-11-33?

  1. TEAM
  2. MEAT
  3. TAME
  4. MATE

Answer:

95. coding-decoding-s10-q05

A message was coded by moving every letter the same number of places forward in the alphabet, and ZEBRA became DIFVE. How many places was each letter moved?

  1. 2
  2. 3
  3. 4
  4. 5

Answer:

96. coding-decoding-s10-q06

A message was coded by moving every letter four places forward in the alphabet. Which word was coded as QSRXL?

  1. MONEY
  2. MOUTH
  3. MOTHS
  4. MONTH

Answer:

97. coding-decoding-s10-q07

In a code, each letter is replaced by the alphabet position of the letter two places after it, so A is written 3. Which word is written 5-3-22?

  1. EAT
  2. CAT
  3. CAR
  4. ACT

Answer:

98. coding-decoding-s10-q08

In a code, a word is written as a single number: the alphabet positions of its letters are added together and the total is then multiplied by the number of letters. What number stands for FIG?

  1. 66
  2. 69
  3. 72
  4. 75

Answer:

99. coding-decoding-s10-q09

In a code, LIME is written NKOG and PEAR is written RGCT. Using the same rule, how is FISH written?

  1. HKSJ
  2. HJUJ
  3. GJTI
  4. HKUJ

Answer:

100. coding-decoding-s10-q10

A word was coded by moving each letter three places back in the alphabet and then writing the result backwards, producing BZX. What was the original word?

  1. AXE
  2. ACE
  3. ICE
  4. EAT

Answer: