Question

find 23×74 using identity ​

Answer 1

Answer:

Step-by-step explanation:

66 × 74

In this question we can apply ( a + b ) ( a - b ), but we have to assume( compare ) the value. In the formula a is common in both, we can get a( compared value ) in the question by mean / average method.

a =    66+74/2=  140/2  =   70

Therefore, if we split 66 and 74, one number will be 70.

66 = 70 - 4

74 = 70 + 4

 

Now,

( 66 ) × ( 74 )

( 70 - 4 ) × ( 70 + 4 )

By the method given above.

( 70 )^2 - ( 4 )^2

4900 - 16

4884.

∴ 66 × 74 = 4884

Answer 2

Identity

a² - b² = ( a + b )( a - b )

Solving

( 48.5 - 25.5 )( 48.5 + 25.5 )

(48.5)² - (25.5)²

2352.25 - 650.25

1702

Answer

So, the answer is 1702.

Thank you.

Extra Information for manipulation

( You can think of 48.5 and 25.5 by taking average of 23 and 74 that is 48.5 and then manipulating for required data. )