15789 = XTZAL, 2346 = NPSU; 23549 = ?

Solution: NPTSL. Direct digit-to-letter map.

623 = 49, 516 = 62, 438 = 89; 583 = ?

Solution: 98. Sum of the squares of the digits: 25 + 64 + 9.

APPLE = 05, LIONS = 96; WALLET = ?

Solution: 37. Position sum 73 written backwards.

What are the common traps in Number / symbol coding questions?

Off-by-one positions: J = 10, S = 19, T = 20; a one-place slip changes every answer. Added vs multiplied count: SINGLE = 66 + 6, but FIRE = 38 × 4; test the example, never assume. Forward vs reverse order: when the code has more digits than letters, check whether it starts from the last letter.

Start here · the first lesson of Number / symbol coding

Number / symbol coding

Coding-Decoding · for IPMAT Indore, IPMAT Rohtak and JIPMAT

The idea

A word is turned into a number through its letters' alphabet positions (sums, products, squares, counts), or digits are mapped one-to-one to letters or symbols by a table. JIPMAT asks one or two every year (CAT = 6423, HE = 418, GREEN = 1677209, DRIVER = 12); Rohtak 2020 had a digit-to-letter code.

Textbook vs exam method

Textbook method

Compute the alphabet positions of the example word, try candidate functions (sum, sum × length, product, square, concatenation with an offset) until one reproduces the given code, then apply it to the asked word.

Exam method

Size test. CAT → 6423 has one or two digits per letter: positions with +3. HE → 418 is far too big for a sum: a product (reverse positions 19 × 22).
Count test. DRIVER = 12, PEDESTRIAN = 20: twice the letter count. SHOULD = 42, ASPIRANT = 72: n(n + 1).
Sum test. TO = 35 = 20 + 15. SINGLE = 72 = 66 + 6 letters. FIRE = 152 = 38 × 4 letters. KITE = 2025 = 45².
Direction test. GREEN → 1677209: positions +2 written from the last letter (N 16, E 7, E 7, R 20, G 9).
Tables. Map each digit from the examples (15789 = XTZAL), then read the asked number. With exception rules, check the first and last digit first.