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Question
Evaluate the following, using suitable identity
990 × 1010
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Solution
990 × 1010 = (1000 – 10)(1000 + 10)
Taking a = 1000 and b = 10, then
(a – b)(a + b) = a2 – b2 becomes
(1000 – 10)(1000 + 10) = 10002 – 102
990 × 1010 = 1000000 – 100
990 × 1010 = 999900
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