Question

Find a whole number such that when one of its digit is erased, the resulting number is equal to one-ninth of the original number. The resulting number is also a multiple of 9.

Answer 1

90

If units digit is removed left over number is 9

Which is 1/9 th of 90

And 90/9=10

Answer 2

Given,

The following hints are given -

when one of its digits is erased, the resulting number is equal to one-ninth of the original number

the resulting number is also a multiple of 9.

To find,

The whole number

Solution,

We have been given in one of the hints that if "one digit is erased", which means a required number is a two-digit number

Also, we know that the number is a multiple of 9, so it has to be a part of the table of 9

So, using the trial and error method, we get the number 90 where

If the units digit is removed remaining number is 9

Which is 1/9th of 90

And 90/9 = 10

So, it fills all the three criteria given

Thus, The whole number is 90