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Answers for Subtraction worksheet

It is important to note that these suggested solutions are just one of the many possible strategies that children may use.

1.

766 - 4 - 96
Possible strategy: grouping
Instead of subtracting 4 then 96, subtract 100.
766 - 4 - 96
= 766 - 100
= 666

2.

104 - 97 = 7
Possible strategy: equal addition
104 - 97
= (104 + 3) - (97 + 3)
= 107 - 100
= 7

3.

1 002 - 7 = 995
Possible strategy: subtraction in stages
1 002 - 2 = 1 000
1 000 - 5 = 995

4.

40 000 - 1 100 = 38 900
Possible strategy: subtraction in stages
40 000 - 1000 = 39 000
39 000 - 100 = 38 900

5.

1 950 - 351 = 1 599
Possible strategy: subtraction in stages
1 650 - 50 = 1 600
1 950 - 300 = 1 650
1 600 - 1 = 1 599

6.

13 000 - 99 = 12 901
Possible strategy: rounding
13 000 - 100 + 1
= 12 900 + 1
= 12 900

7.

5 241 - 900 = 4 341
Possible strategy: rounding
5 241 - 1 000 + 100
= 4 241 + 100
= 4 341

8.

7 243 562 - 999 999 = 6 243 563
Possible strategy: rounding
999 999 is nearly 1 million.
7 243 562 - 1 million = 6 243 562
Then add 1 to get 6 243 563

9.

876 - 123 = 753
Possible strategy: subtraction in stages
876 - 100 = 776
776 - 20 = 756
756 - 3 = 753

10.

2 003 - 1 997 = 6
Possible strategy: equal addition
(2 003 +3) - (1997 + 3)
= 2 006 - 2 000
= 6

11.

$193 - $126 = $67
Possible strategy: complementary addition
Firstly add 4 to 126 to give 130. Then add 60 to 130 to give 193. Add a final 3 to get 193. Altogether 67 has been added to 126 to give 193. Therefore the difference between the two amounts is $67.

12.

54 321 - 50 321 = 4 000
Students may complete this problem by seeing that the 4 in 54 321 represents 4 thousands. Therefore 50 321 needs to be subtracted to leave only 4 000. Reading the numbers in words makes this strategy more obvious.

13.

2100 - 1901 = 199
Possible strategy: working with well known facts
It is 99 years from 1901 to 2000 and 100 years from 2000 to 2100. So altogether it is 199 years.

14.

$30 - $8.95 - $8.95 - $7.50 = $4.60
Possible strategy: rounding
Round both $8.95 to 9 dollars
30 - 9 = 21
21 - 9 = 12
12 - 7.5 = $4.50
Now add the extra 10 cents from the rounding:
$4.50 + 10 cents = $4.60

15.

Mozart was 14 years older.
Possible strategy: complementary addition
To find the difference between 1756 and 1770 first add 4 to 1756 to give 1760 and then add 10 to give 1770. This is a difference of 14.

Mozart lived 35 years.
Possible strategy: equal addition
(1791 + 4) - (1756 + 4)
= 1795 - 1760
= 35

Beethoven lived 57 years
Possible strategy: complementary addition
Add 30 to 1770 to get to 1800. Then add another 27 to get to 1827. Therefore the difference is 57.

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