TOPIC
MY PROGRESS
Pug Score
0%
Best Streak
0 in a row
Study Points
+0
Overview
Practice
Watch
Read
Next Steps
Get Started
Get unlimited access to all videos, practice problems, and study tools.
Unlimited practice
Full videos
Back to Menu
Topic Progress
Pug Score
0%
Videos Watched
0/0
Best Practice
No score
Read
Not viewed
Best Streak
0 in a row
Study Points
+0
Overview
Practice
Watch
Read
Next Steps
Overview
3rd Grade Math
11. 3.NBT.A.2
11.11 Subtraction using Estimation
Subtraction Using Estimation
Round numbers to the nearest ten or hundred, subtract the rounded values, and use that estimate to check whether your exact answer is reasonable.
What You'll Learn
Round each number to the nearest ten or hundred before subtracting to make the numbers easier to work with
Subtract the rounded numbers to find an estimated difference, such as \( 430 - 190 = 240 \)
Compare an exact subtraction answer to the estimate to check whether the exact answer is reasonable
Recognize that an estimate is not the exact answer, only a quick way to spot a mistake
Apply rounding rules consistently, rounding both numbers to the same place value before subtracting
What You'll Practice
1
Rounding two-digit and three-digit numbers before subtracting
2
Estimating differences for numbers up to 1000
3
Comparing estimated answers to check reasonableness
Why This Matters
Estimation helps you quickly check if your answers make sense and solve real-world problems faster. Whether you're calculating change at a store, measuring ingredients, or budgeting money, estimating differences lets you make smart decisions without needing exact numbers every time.
This Unit Includes
1 Video lesson
Practice exercises
Learning resources
Skills
Estimation
Rounding
Subtraction
Place Value
Mental Math
Number Sense
OH Curriculum Aligned