Question

find the square of 42 by using column method ​

Answer 1

Solution:

We know that

$( {a + b)}^{2} = {a}^{2} + 2ab + {b}^{2} \\ \\ here \\ 42 = 40 + 2 \\ \\ {(40 + 2)}^{2} = ( {40)}^{2} + 2(40)(2) + {2}^{2} \\ \\ = 1600 + 160 + 4 \\ \\ ( {40)}^{2} = 1764$
put those values in the column,while writing the answer

Hope it helps you.

Answer 2

Answer:

42²

a=4² ;b=2²

a² 2ab : b²

(4)²=16 2×4×2=16 (2)²=4

+1=17 6 4

Ans=1764