Common Core Math Vocabulary

# Compatible Numbers - Definition with Examples

## Let's learn!

**What are compatible numbers?**

To be ‘compatible’ means to exist or work successfully with something or someone else.

In math, compatible numbers can be defined as the numbers that are easy to add, subtract, multiply, or divide mentally.

Compatible numbers are close in value to the actual number that make the estimating the answer and computing problems easier.

One can make numbers compatible by rounding them to the nearest ten, twenty, fifty or hundred.

For instance, if we are given the problem 493 + 549, we can make the numbers compatible by rounding them up to the nearest tens or hundreds. 490 and 550 (rounded to the nearest tens) or 500 and 500 (rounded to the nearest hundreds) are much easier to solve.

So, we know the answer is about 1040 or 1000.

## Let's sing!

*Big number problems to solve – Don’t dread!*

*Make the numbers compatible – Just go ahead!*

*They will make it easy to solve, even in your head!*

## Let's do it!

Take your child out for grocery shopping. After picking up the items to be bought, ask your child to estimate the total bill by making the cost of items compatible.

## Related math vocabulary

The Complete K-5 Math Learning Program Built for Your Child