Page 44 - ICSE Math 4

Step 3: 6 – ? = 3

In the hundreds column, to fi nd the missing Th H T O
subtrahend, subtract the diff erence from
? 6 8 2
the minuend.
– 5 3 4 1
6 – 3 = 3 (minuend – diff erence = subtrahend)
2 3 4 1
So, write 3 in the blank space.

Step 4: ? – 5 = 2

In the thousands column, to fi nd the Th H T O
missing minuend, add the subtrahend to
the diff erence. 7 6 8 2
– 5 3 4 1
5 + 2 = 7 (subtrahend + diff erence = minuend)
2 3 4 1
So, write 7 in the blank space.

Estimating the Difference

To es mate the diff erence between two numbers, round off the given minuend and
subtrahend to the nearest 10; 100; 1,000, etc., and then subtract.

Example 6: Find the diff erence between 6,875 and 3,256 using es ma on method by
rounding off each number to the nearest 100. Verify the result by fi nding the
actual value.

Solu on: Actual Value Es mated Value

Th H T O Th H T O
6 15
6 8 7 5 6 9 0 0 (6,875 is rounded off to 6,900)

– 3 2 5 6 – 3 3 0 0 (3,256 is rounded off to 3,300)

3 6 1 9 3 6 0 0

The actual diff erence 3,619 when rounded off to the nearest 100 is 3,600
(es mated diff erence).

Exercise 4.3

1. Subtract the following numbers using the expanded form.

(a) 465 from 3,897 (b) 6,784 from 7,895 (c) 4,385 from 5,603

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