4th Grade Math · Parent guide
What Math Should a 4th Grader Know?
Complete Parent Guide
By the end of 4th grade, your child should add and subtract multi-digit numbers with the standard method, multiply up to a four-digit number by a one-digit number and a two-digit number by a two-digit number, divide numbers up to four digits by a one-digit number (with remainders), find equivalent fractions and compare fractions like 2/3 and 3/4, add and subtract fractions with the same denominator, write fractions with denominators 10 and 100 as decimals, and measure angles with a protractor. The Common Core names three focus areas for grade 4: multi-digit multiplication and division, fractions, and classifying shapes by their lines and angles.
Reviewed against the Common Core standards.
What 4th Graders Learn in Math, by Domain
These are the Common Core State Standards for Grade 4 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 4 introduction.
Operations & Algebraic Thinking
Common Core 4.OA- Understand "times as many": 35 = 5 × 7 means 35 is 5 times as many as 7 (4.OA.1, 4.OA.2)
- Solve multi-step word problems, including ones where the remainder has to be interpreted (4.OA.3)
- Find all factor pairs of a number from 1 to 100 and decide whether it is prime or composite (4.OA.4)
- Generate and explain number patterns that follow a rule (4.OA.5)
Number & Operations in Base Ten
Common Core 4.NBT- Know that each place is worth ten times the place to its right, with whole numbers to 1,000,000 (4.NBT.1)
- Round multi-digit numbers to any place (4.NBT.3)
- Add and subtract multi-digit numbers fluently with the standard algorithm (4.NBT.4)
- Multiply up to four digits by one digit, and two digits by two digits, explaining with area models (4.NBT.5)
- Divide up to four-digit numbers by one-digit numbers, with remainders (4.NBT.6)
Number & Operations: Fractions
Common Core 4.NF- Explain and generate equivalent fractions, such as 2/3 = 8/12 (4.NF.1)
- Compare fractions with different numerators and denominators, for example against 1/2 (4.NF.2)
- Add and subtract fractions and mixed numbers with like denominators (4.NF.3)
- Multiply a fraction by a whole number, such as 3 × 2/5 = 6/5 (4.NF.4)
- Write tenths and hundredths as decimals (0.62 = 62/100) and compare decimals to hundredths (4.NF.5-4.NF.7)
Measurement & Data
Common Core 4.MD- Convert within one system: km to m, hours to minutes, pounds to ounces, feet to inches (4.MD.1)
- Solve word problems about distance, time, volume, mass and money (4.MD.2)
- Use area and perimeter formulas for rectangles, including finding a missing side (4.MD.3)
- Measure angles in degrees with a protractor and find unknown angles by adding or subtracting (4.MD.5-4.MD.7)
Geometry
Common Core 4.G- Draw and identify points, lines, rays, angles, and parallel and perpendicular lines (4.G.1)
- Classify shapes by parallel or perpendicular sides and by angle size, and identify right triangles (4.G.2)
- Find and draw lines of symmetry (4.G.3)
What 4th 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.
Remainders in context (4.OA.3)
150 students are going on a trip. Each van holds 8 students. How many vans are needed?
Answer: 19 vans. 150 ÷ 8 = 18 remainder 6, and the 6 extra students still need a van. Answering "18 R6" is the classic 4th grade mistake.
Two-digit multiplication (4.NBT.5)
What is 36 × 27? Show it with an area model.
Answer: 972. Split it into 30 × 20 = 600, 30 × 7 = 210, 6 × 20 = 120 and 6 × 7 = 42, then add.
Comparing fractions (4.NF.2)
Which is greater, 5/8 or 3/5?
Answer: 5/8. One way: 5/8 = 25/40 and 3/5 = 24/40. Another: 5/8 is 1/8 more than a half, 3/5 is 1/10 more than a half, and 1/8 is bigger than 1/10.
Unknown angle (4.MD.7)
A right angle is split into two angles. One is 35°. What is the other?
Answer: 55°. A right angle is 90°, and 90 - 35 = 55.
Signs Your 4th Grader May Be Behind in Math
Fourth grade asks children to put several skills together, so gaps that were small in 3rd grade start to show. Watch for these:
- !Still slow on times tables like 7 × 8 or 6 × 9, which makes long division and two-digit multiplication painful
- !Gives "18 R6" as the answer to a word problem that needs a whole number of vans or boxes
- !Thinks 1/3 + 1/3 = 2/6, adding the bottoms as well as the tops
- !Thinks 0.5 is smaller than 0.25 because 5 is smaller than 25
- !Cannot read a protractor, or reads the wrong scale and gets 120° for a 60° angle
Short At-Home Activities (10 Minutes or Less)
Fix the slow facts first
Time one set of 10 multiplication facts each day and write down the ones that take more than a few seconds. Fourth grade multiplication and division depend on these.
Decimals through money
Ask which is more, $0.70 or $0.65. Then write $0.70 as 70/100 and 7/10. Money makes tenths and hundredths concrete.
Benchmark against one half
When comparing fractions, ask "is it more or less than a half?" first. 3/8 is less than 4/8, which is a half. 4/7 is more than a half, because 4 is more than half of 7. That settles most comparisons fast.
Measure angles around the house
Use a protractor on an open door, a laptop screen or a slice of pizza. Estimate first, then measure.
Ask "what does the remainder mean?"
When you share 23 cookies among 4 people, ask what happens to the 3 left over. Rounding up, dropping it, or splitting it are all real answers depending on the story.
Find Your Child's Exact Level
Fourth grade is where small gaps become big problems. Our diagnostic checks multiplication, division, fractions, decimals and geometry and shows you exactly which 4th grade skills need work, in about 10 minutes.
Start the DiagnosticQuestions Parents Ask
Should a 4th grader be able to do long division?
Yes, with a one-digit divisor. The standard asks 4th graders to divide numbers up to four digits by a one-digit number and find the remainder, and to explain it with arrays, area models or equations (4.NBT.6). Dividing by two-digit numbers comes in 5th grade.
How well should my 4th grader know the times tables?
They should be automatic. The standards expect all one-digit products from memory by the end of 3rd grade (3.OA.7), and 4th grade builds on them for multi-digit multiplication, division, factors and equivalent fractions.
My 4th grader is confused by fractions with different denominators. Is that normal?
Yes, it is one of the hardest 4th grade skills. Comparing fractions with different denominators (4.NF.2) is new this year. Fraction strips and the "more or less than half" trick help. Adding fractions with unlike denominators waits until 5th grade.
Do 4th graders learn decimals?
Yes, tenths and hundredths. They learn to write 62/100 as 0.62, place decimals on a number line and compare them (4.NF.6, 4.NF.7). Adding and multiplying decimals comes in 5th grade.
What geometry is in 4th grade?
Lines, rays and angles. Fourth graders measure angles with a protractor, classify shapes by parallel and perpendicular sides and angle size, identify right triangles and draw lines of symmetry.