Into Math Grade 3, Unit 1: Whole Number Place Value, Addition, and Subtraction
In this unit, your child uses place value, the value of each digit by where it sits, to round numbers to the nearest 10 or 100 and to add and subtract within 1,000. Rounding helps children estimate and check their answers. This opens third grade with strong number sense, and the next unit begins multiplication and division.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 1?
- Rounding numbers to the nearest 10 or 100, such as 462 to 460 or 500, by deciding which is closer. Learn more: Rounding to the nearest 10 or 100
- Adding and subtracting within 1,000 by breaking numbers into hundreds, tens, and ones and regrouping, or trading, when needed. Learn more about adding within 1,000: Adding within 1,000 · Learn more about subtracting within 1,000
Sample questions to try together
These are real questions from our practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
What is 43 rounded to the nearest 10?
- 50
- 40
- 30
How you can help
- Round numbers you spot on a walk or ride, such as a house number like 347, to the nearest 10 and the nearest 100, and ask how your child decided which is closer.
- Estimate before adding: if one book has 238 pages and another has 191, round to guess about 430 in all, then add exactly to check.
- Open a book to two pages, such as 305 and 128, and find the difference together, then check by adding the answer to the smaller page number.
Where kids can get stuck
- Looking at the wrong digit, such as checking the 7 when rounding 347 to the nearest hundred.
- Rounding the tens up but forgetting to change the ones to zero, so 347 to the nearest ten becomes 357 instead of 350.
- Subtracting the smaller digit from the larger in each column, so 452 - 178 comes out as 326 instead of 274.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- place value
- The value a digit has because of its place, like the 4 in 470 meaning 4 hundreds.
- digit
- One of the symbols 0 through 9 used to write numbers.
- round
- To change a number to a nearby, friendlier number, like 47 to 50.
- nearest ten
- The multiple of 10 closest to a number, like 50 for 47.
- nearest hundred
- The multiple of 100 closest to a number, like 300 for 287.
- estimate
- A close guess, often made by rounding, to check whether an answer makes sense.
- regroup
- To trade 10 ones for 1 ten, or 10 tens for 1 hundred, and back.
- sum
- The answer to an addition problem.
- difference
- The answer to a subtraction problem.
Want to help your child master place value and rounding?
In Bobby's Math Club, your child practices these skills at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free.
Join the club
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
Which math standards does Into Math Grade 3 Unit 1 cover?
Into Math Grade 3 Unit 1 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.