Page 33 - ICSE Math 4

Finding the Missing Digits

Let’s understand how to fi nd the missing digits in an addi on sum by considering the

given example.
Example 5: Find the missing digits.

Th H T O

? 3 ? 4

+ 6 2 5 ?
8 ? 4 1

Solu on: Step 1: Look at the ones column. Th H T O
1 is smaller than 4. 1
? 3 ? 4
So, we fi nd the smallest number which
when added to 4 gives a sum which has 1 + 6 2 5 7

in the ones place. 8 ? 4 1
11 is the smallest number with 1 in the ones place.

Thus, 4 + ? = 11.

Now, 11 – 4 = 7 (sum – one addend = other addend).
So, we write 7 in the blank space.

Since 11 is a 2-digit number, keep the 1 as it is and carry over 1 to the
tens place.

Step 2: Look at the tens column.

1 + ? + 5 = 4

6 + ? = 4

4 is smaller than 6.

So, we fi nd the smallest number which Th H T O
when added to 6 gives a sum which has 4 1 1
? 3 8 4
in the ones place.

14 is the required number. + 6 2 5 7
8 ? 4 1
Thus, 6 + ? = 14.

Now, 14 – 6 = 8 (sum – one addend = other addend).

So, we write 8 in the blank space.

Since 14 is a 2-digit number, keep 4 as it is and carry over 1 to the
hundreds place.

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