3rd Grade Math · Parent guide
What Math Should a 3rd Grader Know?
Complete Parent Guide
By the end of 3rd grade, your child should know all products of two one-digit numbers from memory, multiply and divide within 100, understand fractions like 3/4 as numbers that sit on a number line, find area by tiling and multiplying, solve perimeter problems, round to the nearest 10 or 100, and solve two-step word problems with all four operations. The Common Core standards name four focus areas for grade 3: multiplication and division, fractions (starting with unit fractions like 1/4), area, and two-dimensional shapes. Here is what each one means, with sample problems, signs of trouble and quick activities.
Reviewed against the Common Core standards.
What 3rd Graders Learn in Math, by Domain
These are the Common Core State Standards for Grade 3 math, grouped by domain and put into plain English. Many states use them as written or in an adapted version, so your school's wording may differ slightly. The code after each skill is the standard it comes from, and each domain links to the full text on the Common Core site. Read the official Grade 3 introduction.
Operations & Algebraic Thinking
Common Core 3.OA- Understand 5 × 7 as 5 groups of 7, and 56 ÷ 8 as sharing 56 into 8 equal groups (3.OA.1, 3.OA.2)
- Solve multiplication and division word problems within 100 (3.OA.3)
- Use properties to multiply, such as 8 × 7 = (8 × 5) + (8 × 2) (3.OA.5)
- Multiply and divide within 100 fluently, and by the end of the year know all products of two one-digit numbers from memory (3.OA.7)
- Solve two-step word problems with all four operations, using a letter for the unknown, and check that the answer is reasonable (3.OA.8)
Number & Operations in Base Ten
Common Core 3.NBT- Round whole numbers to the nearest 10 or 100 (3.NBT.1)
- Add and subtract within 1000 fluently (3.NBT.2)
- Multiply a one-digit number by a multiple of 10, such as 9 × 80 (3.NBT.3)
Number & Operations: Fractions
Common Core 3.NF- Understand 1/4 as one part when a whole is split into 4 equal parts, and 3/4 as three of those parts (3.NF.1)
- Place fractions on a number line (3.NF.2)
- Recognize simple equivalent fractions such as 1/2 = 2/4 and 4/6 = 2/3, and write whole numbers as fractions (3 = 3/1) (3.NF.3)
- Compare fractions with the same top or bottom number, such as 3/8 and 3/4 (3.NF.3)
Measurement & Data
Common Core 3.MD- Tell time to the nearest minute and solve elapsed-time problems (3.MD.1)
- Measure liquid volume in liters and mass in grams and kilograms (3.MD.2)
- Read scaled bar graphs where each square may stand for 5 or 10 (3.MD.3)
- Find area by counting unit squares and by multiplying side lengths, and split L-shapes into rectangles (3.MD.5-3.MD.7)
- Solve perimeter problems, including finding a missing side (3.MD.8)
Geometry
Common Core 3.G- Understand that rhombuses, rectangles and squares are all quadrilaterals, and draw quadrilaterals that are none of these (3.G.1)
- Split shapes into parts with equal area and name each part as a unit fraction, such as 1/6 (3.G.2)
What 3rd Grade Math Problems Look Like
Original practice problems written to match the standards above, with the answer and the thinking we would hope to hear.
Two-step word problem (3.OA.8)
A class of 24 students splits into teams of 4. Each team gets 3 balls. How many balls are needed?
Answer: 18. First 24 ÷ 4 = 6 teams, then 6 × 3 = 18 balls.
Fractions on a number line (3.NF.2)
Mark 3/4 on a number line from 0 to 1. Is it closer to 0 or to 1?
Answer: Split the space between 0 and 1 into 4 equal jumps and count 3 of them. 3/4 is closer to 1.
Comparing fractions (3.NF.3)
Which is bigger, 3/8 or 3/4 of the same pizza?
Answer: 3/4. Both have 3 pieces, but fourths are bigger pieces than eighths. A child who says 3/8 because 8 is bigger than 4 is treating fractions like whole numbers.
Area of an L-shape (3.MD.7)
A garden is shaped like an L. It can be split into a 4 m by 3 m rectangle and a 2 m by 2 m square. What is its area?
Answer: 16 square meters. 4 × 3 = 12, plus 2 × 2 = 4.
Elapsed time (3.MD.1)
Soccer practice starts at 3:45 and lasts 50 minutes. When does it end?
Answer: 4:35. 15 minutes gets to 4:00, and 35 more minutes is 4:35.
Signs Your 3rd Grader May Be Behind in Math
Third grade is where multiplication and fractions start, so gaps show up fast. Watch for these, especially after winter break:
- !Still skip-counts from zero to find 6 × 7 late in the year, when the standards expect one-digit products from memory by the end of 3rd grade
- !Can multiply but cannot tell you what 24 ÷ 6 means or which operation a word problem needs
- !Thinks 1/8 is bigger than 1/4 because 8 is bigger than 4
- !Mixes up area and perimeter, or adds the sides when asked for area
- !Cannot read time to the minute on an analog clock
Short At-Home Activities (10 Minutes or Less)
Five facts a day
Pick one times table and quiz just five facts at dinner, mixing in division: "7 × 6? And 42 ÷ 7?" Learning them as pairs makes division far easier.
Fold paper fractions
Fold strips of paper into halves, fourths and eighths and lay them side by side. Ask which is bigger, 1/4 or 1/8, and let your child see it.
Tile a rug
Use sticky notes or paper squares to cover a placemat or book, then count rows and columns. Show that 5 rows of 4 is the same as 5 × 4.
Time the next activity
Before a TV show or practice, ask "if it starts at 4:20 and lasts 35 minutes, when does it end?" Elapsed time is a 3rd grade standard many children find hard.
Round the grocery bill
Round prices to the nearest 10 cents or dollar and add them up in your head before checkout.
Find Your Child's Exact Level
Third grade is where multiplication and fractions begin. Our diagnostic checks facts, fractions, area and word problems and shows you exactly which 3rd grade skills are solid and which need work, in about 10 minutes.
Start the DiagnosticQuestions Parents Ask
Should my 3rd grader know all the times tables?
Yes, through 9 × 9 by the end of the year. The standard says students should know from memory all products of two one-digit numbers by the end of grade 3 (3.OA.7). It does not mention 11s and 12s; your school may add them.
Why does my child have to draw fractions on a number line?
Because the 3rd grade standards treat a fraction as a number with a place on the number line (3.NF.2), not only as a slice of pie. That idea is what lets children compare fractions and later add them in 4th and 5th grade.
My 3rd grader can multiply but freezes on word problems. Is that normal?
It is very common. Third graders now meet two-step problems with all four operations (3.OA.8). Ask "what do we know, what are we finding, and what is the first step?" and have your child draw the groups before writing numbers.
What is the difference between area and perimeter in 3rd grade?
Perimeter is the distance around a shape, added up in units like feet. Area is how many unit squares cover it, found by multiplying the side lengths of a rectangle. Third graders also learn that two rectangles can have the same perimeter but different areas (3.MD.8).
When do 3rd graders learn division?
At the same time as multiplication. Third graders learn division as sharing into equal groups and as a missing-factor problem: 32 ÷ 8 asks "8 times what is 32?" (3.OA.2, 3.OA.6). By the end of the year they should multiply and divide within 100 fluently (3.OA.7), so practice the facts as pairs.