Rounding Numbers

Alright boys and girls. Here is the work we did with Rounding. 

Remember the steps!

1. Find the Benchmark Numbers

        ______ 46 ______

The Benchmark Numbers for 46 are 40 and 50.

        __40__ 46 __50__

2. Now imagine the number line and decide "Is 46 closer to 40 or 50?" Boom!! 46 is only 4 away from 50 and it is 6 away from 40!

       __40__ 46 __50__

You can now do the same thing with a hundred number. Take a look:

      __300__ 324 __400__

Moving on!

You have mastered rounding to the tens and hundreds...
so now we are ready for the challenging problems.

Let's round to the TENS with a hundreds number.

1. Start the same way. Find the Benchmark Numbers. 

__270__ 274 __280__                         

2. Same thing again, "Which Benchmark Number is our number closest to?" 

A hint is to ask "Is 74 closer to 70 or 80?"

Well 74 is only 4 away from 70 and 6 away from 80. 

__270__ 274 __280__                         

You can now do the same thing rounding to the HUNDREDS with a thousands number!

__3,200__ 3,289 __3,300__

Now let's apply what we know to addition and subtraction problems. 

Check out our anchor charts for Estimation using addition and subtraction! 

1. Round first

2. Then solve

3. Are the answers close?