Saxon Math Grade 2, Section 4: Three-Digit Operations & Geometry
In this unit, your child adds and subtracts three-digit numbers, regrouping across hundreds, tens, and ones, and adds or takes away 10 or 100 mentally. They also study shapes, naming them by sides, angles, and faces, and split shapes into halves, thirds, and fourths. Next comes arrays, an early look at multiplication.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Section 4?
- Adding and subtracting three-digit numbers on paper, lining up hundreds, tens, and ones and regrouping as needed. Learn more about adding within 1,000: Adding within 1,000 · Learn more about subtracting within 1,000
- Finding 10 or 100 more or less than three-digit numbers mentally by changing one digit. Learn more: Adding or taking away 10 or 100 mentally
- Naming and drawing triangles, quadrilaterals, pentagons, hexagons, and cubes by counting sides, angles, and faces. Learn more: Naming triangles, hexagons, cubes, and more
- Dividing circles and rectangles into equal halves, thirds, and fourths and naming each share. Learn more: Halves, thirds, and fourths of shapes
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
A toy store had 450 toy cars and sold 120 of them. How many toy cars are left?
- 320
- 570
- 330
How you can help
- Add two three-digit numbers you see, like the page counts of two books, and let your child talk through each column.
- Ask "100 more?" and "10 less?" for a number on a sign or a mailbox, and talk about which digit changes.
- Fold paper circles or squares into halves and then fourths, and ask your child whether all the parts are equal and how they know.
Where kids can get stuck
- Lining up numbers on the left instead of the right, so 245 + 38 adds the 3 to the 2 hundreds.
- Counting the corners of a shape twice because they did not mark where they started.
- Thinking a shape cut into 4 pieces of different sizes shows fourths.
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
- hundreds
- Groups of 100. In 706, the 7 means 7 hundreds, or 700.
- regroup
- Trading 10 ones for 1 ten, or 1 ten for 10 ones, to add or subtract.
- mentally
- In your head, without writing it down or using objects.
- triangle
- A flat shape with 3 straight sides and 3 angles.
- pentagon
- A flat shape with 5 straight sides and 5 angles.
- hexagon
- A flat shape with 6 straight sides and 6 angles.
- cube
- A solid shape with 6 square faces that are all the same size.
- half
- One of two equal shares of a whole.
- fourth
- One of four equal shares of a whole, also called a quarter.
Ready to build your child’s confidence with three-digit math and shapes?
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 Saxon Math Grade 2 Section 4 cover?
Saxon Math Grade 2 Section 4 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.