Page 54 - Start Up Mathematics_3

Solution: Th H T O
? 8 1 2 11 1 Step 1: Subtract the ones. 1 – 6 is not possible.

Borrow 1 ten (or 10 ones) from the tens
– 6 ? 8 6
place.
3 5 ? 5 10 ones + 1 one = 11 ones

To get the missing digit, subtract 6
from 11.

11 – 6 = 5

Th H T O

11 Step 2: Subtract the tens. 1 – 8 is not possible.
? 7 8 1 2 11 1 Borrow 1 hundred (or 10 tens) from the
– 6 ? 8 6 hundreds place.

3 5 3 5 10 tens + 1 ten = 11 tens

To get the missing digit, subtract 8
from 11.
11 – 8 = 3

Th H T O

11 Step 3: In the hundreds column, to find the
? 7 8 1 2 11 1 missing digit of the subtrahend, subtract
– 6 2 8 6 5 from 7.

3 5 3 5 7 – 5 = 2

Th H T O
11 Step 4: In the thousands column, to find the
9 7 8 1 2 11 1 missing digit of the minuend, add 6

– 6 2 8 6 and 3.
3 5 3 5 6 + 3 = 9

Checking

Th H T O
3 1 5 1 3 5 ← Difference

+ 6 2 8 6 ← Subtrahend

9 8 2 1 ← Minuend

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