Math CentralQuandaries & Queries


Question from gloria, a parent:

the # of marshmallows i use is an even # .it is 2 digit number more than 10 less than 20 the 10th digit half of one many marshmallows i used?

Hi Gloria,

If the number is greater than 10 and less than 20, then it must be 11,12,13,14,15,16,17,18,19.

If you look carefully at these numbers you will notice all these numbers have the same number in the 10's spot. Therefore you now know the 10,s digit number.

Now it should be very easy to calculate the 1's digit number.

I hope this helps out.

About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS