Round to the nearest 10 or 100 and add or subtract within 1,000.
Rounding and Big Sums teaches third graders to round numbers to the nearest 10 and 100 using a number line, estimate answers, and add and subtract within 1,000. Estimation helps kids check whether their answers make sense.
Math course · Grade 3
Rounding and Big Sums · Learning goals
Round numbers to the nearest 10 and 100 using a number line, estimate answers, and add and subtract within 1,000.
Why it matters
Estimating first lets kids spot mistakes: if 298 + 405 should be about 700, an answer of 1,203 must be wrong.
Rounding helps with shopping, time and distance: about how much, about how long, about how far.
Adding and subtracting within 1,000 is a key grade 3 skill that leads to multi-digit math.
Inside Rounding and Big Sums
A short read-aloud lesson first, then hands-on games and a quiz to lock it in.
Step 1 · Lesson
A short read-aloud lesson in 4 steps, with pictures and worked examples.
Step 2 · Game
Round to the nearest ten. (8 problems)
Step 3 · Game
Round to the nearest hundred. (6 problems)
Step 4 · Game
Add and subtract within 1,000. (8 problems)
Step 5 · Game
What number is at the red point? (6 problems)
Lesson preview
This is the real lesson text your child hears, read aloud by a friendly voice.
To round to the nearest 10, find the closest ten. 47 is closer to 50 than to 40.
If the ones digit is 5 or more, round up. If it's 4 or less, round down. 34 rounds to 30.
To round to the nearest 100, look at the tens digit. 362 rounds to 400 because 6 is 5 or more.
Use rounding to estimate: 298 + 403 is about 300 + 400 = 700.
For parents
Learning sticks best when kids use it in real life. Here are simple ideas from this course.
At the store, round prices to the nearest dollar and estimate the total before checkout. Compare your estimate with the real total.
Practice
Real questions from Rounding and Big Sums. Try them with your child, then tap to see the answer.
Question 1
90
Question 2
800
Question 3
347
The full course has 28 questions with instant feedback, stars and rewards. Create a free account to play them all.
Rounding and Big Sums · Questions from parents
Rounding and Big Sums is a grade 3 math course for kids ages 8–9. That is Year 4 maths in the UK and Year 3 in Australia. It also works well for review in the next grade, or as a challenge for a confident younger learner.
Round numbers to the nearest 10 and 100 using a number line, estimate answers, and add and subtract within 1,000. Along the way they practice: Round to 10; Round to 100; Add and Subtract; Number Line Points.
About 10 minutes in total, split into 4 short levels. Most kids finish it over two or three sessions. Progress is saved, so they can stop any time and pick up where they left off.
Rounding and Big Sums is part of SkillBloom Premium, which unlocks every course in every subject. Each subject also has free courses, so your child can try SkillBloom before you decide.
No. Every lesson has a friendly read-aloud voice, questions are read aloud too, and the pictures help kids follow along. Confident readers can turn the voice off.
Yes. SkillBloom is built for homeschooling families. Kids work through lessons, games and quizzes on their own, and the parent dashboard shows what they finished and which skills need more practice. It works on phones, tablets and laptops.
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