SEARCH HOME
Math CentralQuandaries & Queries

search

Question from mary, a parent:

Matt is thinking of two numbers. One number is 9 more than the other number. The sum of the numbers is 45. What are the numbers?

Hi Mary,

You can do this by trial and error but I think you are expected to use algebra.

There are two unknown numbers so give them names. I am going to call them $m$ and $n.$ The first requirement is that

One number is 9 more than the other number.

Algebraically this says that

\[m = n + 9.\]

The second requirement is that

The sum of the numbers is 45.

Write an algebraic expression for this requirement. In this expression replace $m$ using $m = n + 9.$ Solve for $n$ and then you know that $m = n + 9.$

Write back if you need more assistance,
Penny
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