Question

plzz give answer of this trick..

Answer 1

see in the last one the answer is 4 is the square of 2 and 2x10=20

In second last one 81 is the square of 9 and if we multiply 7 it comes 63

In the second one we see that 49 is the square of 7 and if we multiply 6 with 7 we get 42

In the first one we see that 64 is the square of 8 and if we multiply 5 with 8 we get 40

So , here we observe that one number is square and another number is not a square so this is the trick used in this .

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