IGCSE Computer Science Paper 1 Word Scramble: 1.1 Number Systems (Modules 3–17)
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Word scramble
Unscramble the letters and write each key term on the line.
1
UMBNER SAEB
How many different digits a number system uses: denary is base 10 (digits 0-9), binary is base 2 (digits 0-1) and hexadecimal is base 16 (digits 0-9 and A-F).
2
RNYDEA ECALP EUAVL
Each denary column is worth 10 times the column to its right (1, 10, 100, 1000). A number is the sum of each digit times its column value, e.g. 345 = 300 + 40 + 5.
3
YANDRE OT B6-1TI RYNBIA
Work from 32768 down to 1. Write 1 and subtract if the place value fits in the remainder, otherwise write 0. Keep leading zeros so the answer has 16 digits.
4
B7024AF61EC359D8
The 16 hex digits: 0-9, then A=10, B=11, C=12, D=13, E=14, F=15. Each digit stands for one 4-bit value, and F (15) is the largest single hex digit.
5
9046 526 61 1
Hex place values, left to right. Each column is worth 16 times the column to its right. Two hex digits cover 0 to 255 and four hex digits cover 0 to 65535.
6
XHE OT EANYDR
Multiply each hex digit's value (A-F = 10-15) by its column value (1, 16, 256, 4096), then add the results. Example: 2F = 2 x 16 + 15 = 47.
7
EDDIIV YB 61
Divide the denary number by 16 again and again. Read the remainders from last to first, writing 10 to 15 as A to F. Check by converting the hex back to denary.
8
NAIRYB OT EHX
Split the bits into groups of four from the right (nibbles), pad the left group with zeros if needed, then replace each nibble with its hex digit.
Answer Key
IGCSE Computer Science Paper 1 · Modules 3–17
1UMBNER SAEB → number base — How many different digits a number system uses: denary is base 10 (digits 0-9), binary is base 2 (digits 0-1) and hexadecimal is base 16 (digits 0-9 and A-F).
2RNYDEA ECALP EUAVL → denary place value — Each denary column is worth 10 times the column to its right (1, 10, 100, 1000). A number is the sum of each digit times its column value, e.g. 345 = 300 + 40 + 5.
3YANDRE OT B6-1TI RYNBIA → denary to 16-bit binary — Work from 32768 down to 1. Write 1 and subtract if the place value fits in the remainder, otherwise write 0. Keep leading zeros so the answer has 16 digits.
4B7024AF61EC359D8 → 0123456789ABCDEF — The 16 hex digits: 0-9, then A=10, B=11, C=12, D=13, E=14, F=15. Each digit stands for one 4-bit value, and F (15) is the largest single hex digit.
59046 526 61 1 → 4096 256 16 1 — Hex place values, left to right. Each column is worth 16 times the column to its right. Two hex digits cover 0 to 255 and four hex digits cover 0 to 65535.
6XHE OT EANYDR → hex to denary — Multiply each hex digit's value (A-F = 10-15) by its column value (1, 16, 256, 4096), then add the results. Example: 2F = 2 x 16 + 15 = 47.
7EDDIIV YB 61 → divide by 16 — Divide the denary number by 16 again and again. Read the remainders from last to first, writing 10 to 15 as A to F. Check by converting the hex back to denary.
8NAIRYB OT EHX → binary to hex — Split the bits into groups of four from the right (nibbles), pad the left group with zeros if needed, then replace each nibble with its hex digit.