Ex 16.1, 3 Find the values of the letters in each of the following and give reasons for the steps involved.
Here,
A × A ends with A
We put different values of A,
and check which ends with A
∴ A can be 0, 1, 5 or 6
For A = 0
But, 10 × 0 = 0
≠ 90
Which is not true.
∴ A ≠ 0
For A = 1
But, 11 × 1 = 11
≠ 91
Which is not true.
∴ A ≠ 1
For A = 1
But, 11 × 1 = 11
≠ 91
Which is not true.
∴ A ≠ 1
For A = 5
But, 15 × 5 = 75
≠ 95
Which is not true.
∴ A ≠ 5
For A = 6
Here, 16 × 6 = 96
Which is true.
∴ A = 6
Checking
Putting A = 6
Hence verified
∴ A = 6

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.