Question

20. 37 × 3 = 111
37 × 6 = 222
37 × 9 = 333
Now without actually multiplying, evaluate 37 × 21

Answer 1

Hi pupil here's your answer ::

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I want to tell that 20.37 ×3 = 61.11 or i think that you must be writing 37 ×3= 111
so without actual calculating find 37×21
we can write 37= (30+7) and 21 = (30-9)
so let's use the identity a^2-b^2= a-b a+b
= 30^2 -