Page 56 - Start Up Mathematics_4

Example 20: 3,803 – 990 + 1,536 – 838 = ?

1
Solution: 3 8 0 3 Step 1: Add the numbers that do not have a minus sign in
+ 1 5 3 6 front of them.
5 3 3 9

1
9 9 0 Step 2: Add the numbers that have a minus sign in front of
+ 8 3 8 them.
1 8 2 8

4 13
5 3 3 9 Step 3: Subtract the sum of step 2 from the sum of step 1.

– 1 8 2 8
3 5 1 1

So, 3,803 – 990 + 1,536 – 838 = 3,511.

Example 21: 34,755 – 21,035 – 9,345 = ?

Solution: 3 4 7 5 5 Step 1: Subtract the second number from the first one.

– 2 1 0 3 5
1 3 7 2 0

0 13 6 11 10
1
1 3 7 2 0 Step 2: Subtract the third number from their difference.
– 9 3 4 5

4 3 7 5

So, 34,755 – 21,035 – 9,345 = 4,375.

Alternatively,

1 1
2 1 0 3 5 Step 1: Add the numbers that have minus sign.

+ 9 3 4 5

3 0 3 8 0

6 15
3 4 7 5 5 Step 2: Subtract the sum in step 1 from 34,755.
– 3 0 3 8 0

0 4 3 7 5

So, 34,755 – 21,035 – 9,345 = 4,375.

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