Rounding
Estimating Sums & Differences
Adding
Subtracting
100

Rounding 672 to the nearest 10.

670

100

What two addends would you add together when estimating the sum of 723+141 by rounding to the nearest 100?

700+100

100

When adding, what place value must you start in?

The ones place

100

True or False; When doing subtraction you start with the ones place, then the hundreds, then the tens? 

False. It's ones, then tens, and then hundreds. 
200

When rounding 892 to the nearest hundred, what are the 2 the low ten you have to round it to?

800 and 900

200

What two numbers would you subtract when estimating the difference of 345-287 by rounding to the nearest 10?

350-290

200

How do you know you need to regroup when adding?

When you get a sum in the ones or tens place that is larger than 9.

200

How do you know you need to regroup when subtracting?

When you can't subtract numbers in the ones or tens place because the number on bottom is larger/number on top is smaller. 

300

When rounding 756 to the nearest ten, what are the low and high tens? What does it round to?

750 and 760

300

Estimate the sum of 542+159 by rounding each addend to the nearest ten.

540+160=700

300

Do you have to regroup when adding 572+419

Yes, you have to regroup the ones. 

300

Do you have to regroup when subtracting 492-321

No

400

Round 892 to the nearest hundred

900

400

Estimate the sum of 482+325 by rounding to the nearest 100. 

500+300=800

400

Add 291+627=

918

400

Subtract 943-261

682

500

Round 45,427 to the nearest ten

45, 430

500

Estimate the difference of 723-509 by rounding to the nearest 10

720-510=210

500

Add 192+284+357

833

500

Subtract 626-357

269