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(*) Multiplying Two Numbers Less Than
100, But Close To 100:
A.
From algebra we learn:
(100 – a) (100
– b) = 100((100 – a) – b) + ab
B. Using numbers instead of
variables we get the following:
1.
Find the difference between both of the numbers and 100.
2.
Multiply these two values together and write it down.
Make sure the answer takes up 2 place values.
3.
Subtract the difference found in step 1 of one of the numbers with the
remaining number. Write the result.
Ex [1]
98 x 97 =_________.
a)
100 – 98 = 2.
b)
100 – 97 = 3.
c)
2 x 3 = 6. Write 06 to take
up 2 place values.
d)
98 – 3 = 95. Write 95.
(You can also use 97 – 2 = 95)
e)
The answer is 9506.
Ex [2] 88 x 93 =_________.
a)
100 – 88 = 12.
b)
100 – 93 = 7.
c)
12 x 7 = 84. Write 84.
d)
93 – 12 = 81. Write 81.
(You can also use 88 – 7 = 81)
e)
The answer is 8184.
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