Question

Question 70 (ii)

Work out the following multiplication.

$12345679\ast 9\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

Use the result to answer the following question.
What will be 12345679 $\times$ 63?

Answer 1

We have, $12345679\ast 9\_\_\_\_\_\_\_111111111$
Here, we observe that in the product all the digits are same i.e. 1, which is actually the unit digit of the product $9\times 9$, Also, the total of digits in the multiplier is 9.
We have to compute the value of 12345679 $\times$ 63.
Here, the sum of the digits of the multiplier is 9 and unit's digit of the product is 9 and unit's digit of the products of $3\times 9$ is 7.
$\therefore$ 12345679 $\times$ 63 = 777777777