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\ 14-Nov-2025 Bharat Arora Proof-7 Reader’s Sign _______________________ Date __________

Subtracting 1

When we subtract 1 from a number, the difference is the number that comes
just ‘before’ the subtracting number.

a. 26 – 1 = 25 b. 67 – 1 = 66 c. 71 – 1 = 70

before before before

Subtracting a number from itself

When we subtract a number from itself, the difference is 0.

a. 15 – 15 = 0 b. 28 – 28 = 0 c. 79 – 79 = 0

SUBTRACTION ON A NUMBER GRID

To subtract numbers on a number grid, 1 2 3 4 5 6 7 8 9 10
we find the bigger number first and 11 12 13 14 15 16 17 18 19 20

then move left or upwards accordingly. 21 22 23 24 25 26 27 28 29 30

To subtract ones, we move to the left 31 32 33 34 35 36 37 38 39 40

and to subtract tens, we move upwards. 41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
Let us find 28 – 5. 61 62 63 64 65 66 67 68 69 70

We put our finger on 28 and move 71 72 73 74 75 76 77 78 79 80
5 boxes to the left (–5). 81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100

23 24 25 26 27 28
–1 –1 –1 –1 –1

We reach 23. Hence, 28 – 5 = 23.

Let us find 56 – 24. 32 33 34 35 36
–1 –1 –1 –1 –10
24 = 20 + 4 = 2 tens 4 ones
46
We put our finger on 56 and move 2 boxes upwards (–20). –10
We reach 36. 56

From 36, we move 4 boxes left (–4). We reach 32. Hence, 56 – 24 = 32.

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Subtraction