All lessons

Course

3rd Grade Math

Multiply and divide within 100, understand fractions, and find area and perimeter.

Work through the lessons in order, from rounding to independent problem-solving. By the end, you can round numbers to the nearest 10 or 100 and add and subtract within 1,000. You can multiply and divide within 100, know your facts, and find an unknown factor. You can solve two-step word problems and find patterns. You can place fractions on a number line, find equivalent fractions, and compare fractions. You can tell time to the minute, find elapsed time, measure liquid volume and mass, read scaled graphs and line plots, find area and perimeter, and sort quadrilaterals.

How to use these lessons

  • Start at the lesson marked Do this. Go on when you can do the line under the title by yourself.
  • Play the Games first. Then take the Quizzes. Eight of ten correct passes. The Worksheets are on paper. The answers are at the bottom.
  • A short turn is enough. If a lesson is hard, play the one before it again.
  • Practice the multiplication facts a few minutes every day. For fractions, fold paper strips. For area, draw on grid paper. For time, use a real clock, and for liquid volume, use a measuring cup.

Each lesson has games, quizzes, and worksheets.

0 of 49

Place Value and Rounding

  1. 1Numbers to 10,000Read, write, and compare numbers to 10,000.
    • Name the thousands, hundreds, tens, and ones digits.
    • Write 4,372 as 4,000 + 300 + 70 + 2.
    • Compare numbers with >, <, and =.
  2. 2Round to the Nearest TenRound a number to the nearest 10.
    • Find the two tens a number is between on a number line.
    • Round 47 to 50 and 43 to 40.
    • Round a number that ends in 5 up, such as 65 to 70.
  3. 3Round to the Nearest HundredRound a number to the nearest 100.
    • Find the two hundreds a number is between.
    • Look at the tens digit to decide.
    • Round 348 to 300 and 362 to 400.
  4. 4Estimate Sums and DifferencesRound first to estimate an answer.
    • Estimate 412 + 289 as 400 + 300 = 700.
    • Estimate a difference by rounding.
    • Use the estimate to check an exact answer.

Addition and Subtraction Within 1,000

  1. 5Add Within 1,000Add three-digit numbers with regrouping.
    • Line up hundreds, tens, and ones.
    • Regroup ones and tens, as in 358 + 276 = 634.
    • Add three numbers.
  2. 6Subtract Within 1,000Subtract three-digit numbers with regrouping.
    • Regroup a ten or a hundred when needed.
    • Solve problems such as 742 − 368 = 374.
    • Check by adding the answer to the number taken away.
  3. 7Subtract Across ZerosSubtract from numbers with zeros, such as 500 − 237.
    • Regroup across a zero in the tens place.
    • Solve problems such as 403 − 168.
    • Use counting up as another strategy.
  4. 8Addition and Subtraction Word ProblemsSolve word problems with numbers to 1,000.
    • Find what the question asks.
    • Choose to add or subtract.
    • Check that the answer makes sense.

Multiplication

  1. 9Multiplication as Equal GroupsWrite equal groups as a multiplication sentence.
    • See 4 groups of 3 as 4 × 3.
    • Connect repeated addition to multiplication.
    • Name the factors and the product.
  2. 10Arrays and Turning Factors AroundUse an array to show that 3 × 5 = 5 × 3.
    • Write an array as rows × columns.
    • Turn an array to show the commutative property.
    • Draw an array for a fact.
  3. 11Multiply by 2, 5, and 10Know the facts for 2, 5, and 10.
    • Use skip-counting to find products.
    • See that fives end in 0 or 5.
    • See that tens end in 0.
  4. 12Multiply by 0 and 1Know that any number times 0 is 0 and times 1 is itself.
    • Explain 5 × 0 = 0 with empty groups.
    • Explain 7 × 1 = 7 with one group.
    • Use these rules with any number.
  5. 13Multiply by 3 and 4Know the facts for 3 and 4.
    • Find 3s by adding one more group to the 2s.
    • Find 4s by doubling the 2s.
    • Solve word problems with 3s and 4s.
  6. 14Break Apart to MultiplySplit a fact into two easier facts.
    • Find 7 × 6 as 5 × 6 + 2 × 6.
    • Split an array into two parts.
    • Use this to find facts you do not know yet.
  7. 15Multiply by 6, 7, 8, and 9Know the facts for 6, 7, 8, and 9.
    • Find 6s by doubling the 3s.
    • Find 8s by doubling the 4s.
    • Find 9s with the 10s minus one group.
  8. 16Multiply by Multiples of 10Multiply a one-digit number by 10, 20, up to 90.
    • Find 4 × 30 as 4 × 3 tens = 12 tens = 120.
    • Use base-ten blocks to show it.
    • Solve problems such as 6 × 80.

Division

  1. 17Division as SharingShare objects equally and write a division sentence.
    • Share 12 among 3 to get 4 each.
    • Write it as 12 ÷ 3 = 4.
    • Name the dividend, divisor, and quotient.
  2. 18Division as Equal GroupsFind how many groups can be made.
    • Make groups of 4 from 20 to get 5 groups.
    • Use repeated subtraction.
    • Tell sharing problems from grouping problems.
  3. 19Multiplication and Division Fact FamiliesUse a multiplication fact to divide.
    • Write 4 × 6 = 24, 6 × 4 = 24, 24 ÷ 4 = 6, and 24 ÷ 6 = 4.
    • Think “4 times what is 24?” to divide.
    • Divide by 0 and 1, and explain why you cannot divide by 0.
  4. 20Find the Unknown NumberFind the missing number in a multiplication or division equation.
    • Solve 8 × □ = 48.
    • Solve □ ÷ 3 = 5.
    • Solve 56 ÷ □ = 7.
  5. 21Multiply and Divide Within 100Multiply and divide quickly within 100.
    • Know all products of two one-digit numbers from memory.
    • Divide using known facts.
    • Find the facts you still need to practice.
  6. 22Multiplication and Division Word ProblemsSolve word problems with equal groups, arrays, and measures.
    • Draw a picture or an array for the story.
    • Choose to multiply or divide.
    • Write an equation with a letter for the unknown.

Word Problems and Patterns

  1. 23Two-Step Word ProblemsSolve problems that need two operations.
    • Find the hidden question in step one.
    • Use any of the four operations.
    • Example: 3 packs of 8 pencils, then give away 5. How many are left?
  2. 24Equations with a LetterUse a letter for an unknown number.
    • Write n × 4 = 28 for a story.
    • Solve for the letter.
    • Check by putting the number back in.
  3. 25Arithmetic PatternsFind and explain patterns in a table.
    • See that 4 times any number is even.
    • Find patterns in the multiplication table.
    • Explain the pattern in your own words.
  4. 26Is the Answer ReasonableUse estimation and mental math to check an answer.
    • Estimate before you solve.
    • Compare your answer to the estimate.
    • Find and fix an answer that does not make sense.

Fractions

  1. 27Unit FractionsName one equal part of a whole as a unit fraction.
    • Split a whole into equal parts.
    • Name one part as 1/2, 1/3, 1/4, 1/6, or 1/8.
    • See that more parts means smaller parts.
  2. 28Fractions of a WholeName a fraction such as 3/4 from a picture.
    • Read the numerator and the denominator.
    • See 3/4 as three 1/4 parts.
    • Shade a shape to show a fraction.
  3. 29Fractions on a Number LinePlace a fraction on a number line.
    • Split 0 to 1 into equal parts.
    • Mark 2/3 on the line.
    • Place fractions greater than 1, such as 5/4.
  4. 30Equivalent FractionsFind fractions that name the same amount.
    • Show that 1/2 = 2/4 = 4/8 with strips.
    • Find equivalent fractions on a number line.
    • Explain why they are the same size.
  5. 31Whole Numbers as FractionsWrite a whole number as a fraction.
    • Write 3 as 3/1.
    • Write 1 as 4/4 or 6/6.
    • Find whole numbers on a fraction number line.
  6. 32Compare FractionsCompare two fractions with the same numerator or the same denominator.
    • Compare 3/8 and 5/8 by the number of parts.
    • Compare 2/3 and 2/6 by the size of the parts.
    • Use >, <, and =, and check with a model.

Time, Liquid Volume, and Mass

  1. 33Time to the MinuteTell and write time to the nearest minute.
    • Count minutes by fives, then by ones.
    • Read times such as 3:47.
    • Match analog and digital clocks.
  2. 34Elapsed TimeFind how much time has passed.
    • Use a number line to jump from start to end.
    • Find an end time from a start time and a length.
    • Solve problems such as 2:15 to 3:40.
  3. 35Liquid VolumeEstimate and measure liquid volume in liters.
    • Know about how much 1 liter is.
    • Read a measuring container.
    • Add and subtract liters in word problems.
  4. 36MassEstimate and measure mass in grams and kilograms.
    • Know that a paper clip is about 1 gram.
    • Know that a textbook is about 1 kilogram.
    • Solve word problems with grams and kilograms.

Data and Graphs

  1. 37Scaled Picture GraphsRead a picture graph where one picture stands for more than one.
    • Use the key, such as one star = 5 votes.
    • Count a half picture.
    • Make a picture graph with a key.
  2. 38Scaled Bar GraphsRead and make a bar graph with a scale of 2, 5, or 10.
    • Read a bar that ends between two lines.
    • Answer “how many more” questions.
    • Make a bar graph from a table.
  3. 39Line PlotsMeasure to the nearest quarter inch and show it on a line plot.
    • Measure with a ruler marked in halves and fourths.
    • Put an X for each measurement.
    • Find the most common length.

Area and Perimeter

  1. 40Understand AreaFind area by counting unit squares.
    • Say that area is the space inside a shape.
    • Cover a shape with unit squares with no gaps.
    • Use square centimeters and square inches.
  2. 41Area by MultiplyingMultiply length by width to find the area of a rectangle.
    • Connect rows of squares to multiplication.
    • Find the area of a 6 × 4 rectangle.
    • Find a missing side from the area.
  3. 42Area of Combined RectanglesSplit a shape into rectangles and add the areas.
    • Split an L shape into two rectangles.
    • Add the two areas.
    • Show that splitting a different way gives the same area.
  4. 43PerimeterFind the distance around a shape.
    • Add the lengths of all the sides.
    • Find a missing side length from the perimeter.
    • Tell area from perimeter.
  5. 44Same Area, Different PerimeterDraw rectangles with the same area but different perimeters.
    • Draw all rectangles with an area of 12.
    • Find each perimeter.
    • Find rectangles with the same perimeter but different areas.

Shapes

  1. 45QuadrilateralsSort quadrilaterals by their sides and angles.
    • Name squares, rectangles, and rhombuses.
    • See that a square is also a rectangle and a rhombus.
    • Draw a quadrilateral that is none of these.
  2. 46Split Shapes into Equal PartsSplit a shape into parts with equal area and name each part as a fraction.
    • Split a rectangle into 4 equal parts in different ways.
    • Name each part as 1/4 of the whole.
    • Check that the parts have equal area.

Review, Mixed Practice, and Challenges

  1. 47Multiplication and Division ReviewMultiply and divide within 100 without counting.
    • Answer mixed facts quickly.
    • Find unknown numbers in equations.
    • Solve mixed word problems.
  2. 48Fractions and Measurement ReviewSolve mixed problems about fractions, time, area, and perimeter.
    • Compare and place fractions.
    • Find elapsed time.
    • Find area and perimeter.
  3. 49Third Grade Math ChallengeComplete mixed questions covering the major units.
    • Choose the operation without being told.
    • Solve two-step problems by yourself.
    • Find the areas that need more practice.