Question

Find the value of: 71 × 21
1. 1491
2. 1521
3. 1471
4. 1581
5. None of these

Answer 1

Correct Answer - Option 1 : 1491

Concept used :-

Trick to multiply two digit numbers ending in 1.

Method :-

• Multiply the left most digits of both the numbers.
• Add the left most digits of both the numbers.
• Put the result from Step(2) next to the result of Step(1)
• Put 1 next to the result of Step(3)

 

Calculation :-

Let the product be AB1

A = 2 × 7 = 14

B = 2 + 7 = 9

AB1 = 1491

Hence, 1491 is our answer.