An equal-groups story has three numbers: how many groups, how many in each, and the total.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Try it first
Dev bakes 20 muffins. He puts 4 on each plate. How many plates does he fill?
plates
Stuck is fine. Let’s Learn shows the way next. Got it first time? You can jump ahead to Watch an Example.
When to multiply
If you know the groups and the size, and the total is missing, multiply.
When to divide
If you know the total and one of the others, divide.
Draw it first
Sketch the array. The gap in the picture tells you which operation to use.
Step 2: Try It Yourself
Tap and try it out.
7 + 7 + 7 + 7 + 7 + 7 = 42
6 × 7 = 42
42 ÷ 6 = 742 ÷ 7 = 6
6 rows of 7 makes 42.
6 × 7 = 42. 6 and 7 are a factor pair of 42.
Pairs you have found
- 6 × 7
Step 3: In Real Life
Planning a party
36 cookies, 4 to a bag: division tells you 9 bags. 9 bags of 4: multiplication tells you 36 cookies. Same party, and the story tells you which sum.
Step 4: Watch an Example
One step at a time.
Watch Ana Choose
Ana reads: "A florist fills 4 vases. Each vase holds 8 roses. How many roses?"
- Step 1
Ana looks for the three numbers: groups, size, and total.
Watch Leo Choose
Leo reads: "35 marbles are shared equally into 5 jars. How many in each jar?" Leo starts, and you finish.
- Step 1
Leo looks for the three numbers. He sees 35 marbles and 5 jars.
Step 5: Your Turn
Practice makes it stick.
The Ticket Booth
Problem 1 of 12
A ride ticket costs $3. Priya buys 7 tickets. How much does she pay?
dollars
The School Trip
Problem 2 of 12
A minibus holds 10 children. 90 children are going on a trip. How many minibuses are needed?
minibuses
Three Numbers, One Missing
Find the three numbers. Then find the missing one.
Problem 3 of 12
6 tables with 5 chairs at each. How many chairs? Which sentence finds it?
Problem 4 of 12
16 wheels. Each bike has 2 wheels. How many bikes?
bikes
Problem 5 of 12
Sam shares 18 stickers equally onto 3 pages. How many on each page?
stickers
Find the Mistake
One line on each page is a slip. Find it, then fix it.
Problem 6 of 12
Omar reads: "12 balloons shared equally between 4 children. How many each?" One line is a slip. Which?
Omar's answer for: 12 balloons, 4 children
- 1Total 12, children 4, each ?
- 212 × 4 = 48
- Answer48 balloons each
Problem 7 of 12
What should Omar's answer be? How many balloons each?
balloons
Problem 8 of 12
Maya reads: "9 bags with 3 shells in each. How many shells in all?" One line is a slip. Which?
Maya's answer for: 9 bags, 3 shells in each
- 1Bags 9, in each 3, total ?
- 29 ÷ 3 = 3
- Answer3 shells in all
Problem 9 of 12
What should Maya's answer be? How many shells in all?
shells
Which Way?
Pick the way that fits the story.
Problem 10 of 12
Priya has 45 beads. She puts 5 on each string. How many strings? Which way?
Problem 11 of 12
A baker fills 6 trays. Each tray holds 10 buns. How many buns? Which way?
Build the Story
Build it, then check.
Problem 12 of 12
A hall has 40 chairs in rows of 5. Build the array. Put 5 in each row, and enough rows for 40.
1 = 1
1 × 1 = 1
1 ÷ 1 = 1
1 row of 1 makes 1.
Step 6: Quick Check
Show what you know.
Question 1 of 2
5 boxes with 8 pens each. How many pens?
Question 2 of 2
The total is known and the group size is missing. What do you do?
Ready for more?Optional. Past the lesson, for anyone who wants it.
Stretch 1 of 2
Sam has 25 stickers. He wants equal rows with none left over. Which row size works?
Stretch 2 of 2
Ana has 3 boxes of 8 crayons. She shares all of them equally between 4 tins. How many crayons in each tin?
crayons
What You Learned
- Find the three numbers: groups, size, and total.
- Total missing means multiply.
- Total known means divide.
For the grown-up
This lesson is where the child chooses between multiplication and division for equal-group word problems within 100. Multiplication is equal groups before it is a fact to recall. Three fours is three groups of four, and division is the same picture asked from the other end.
Watch for multiplication and division being learned as separate subjects. They are one relationship, and a child who sees that halves what there is to remember.
When they are stuck on a division, ask the multiplication instead: "what times 4 gives 24?" Nearly every child can answer that when they cannot answer 24 divided by 4.
The slip this lesson targets is picking the operation from a word: "each" does not mean multiply, and "shared" is not the only word for division. Have them name the three numbers first: the groups, how many in each, and the total. If the total is the one missing, multiply; if the total is given, divide. Omar's slip multiplies a total that was already known, and his 48 balloons from a pile of 12 is bigger than the pile. Asking "can sharing make more?" catches it. Maya's slip divides when the total is missing; ask her what the 9 and the 3 are before she picks a sign.
Deciding between multiplying and dividing — If the story gives you the number of groups and the size of each group, multiply to find the total. If it gives you the total and one of the two, divide to find the other. Write down which numbers you have been given and which you have been asked for; the operation follows from that.
Draw the groups, or the array — A quick sketch of 4 circles with 6 dots in each settles almost any confusion. If the drawing has too many things to sketch, draw four boxes labeled 6 instead. The point is to see the structure, not to count.
Check the size of the answer — Multiplying by a whole number bigger than one makes things bigger; dividing makes them smaller. If a story about sharing produces an answer bigger than the total you started with, you have divided the wrong way round. This check takes a second and catches the most common error in the chapter.
What is the story asking for? — "4 bags, 6 apples in each. How many apples?" You know the groups and the size. Multiply. 24 "24 apples in 4 bags. How many in each?" You know the total. Divide. 6 "24 apples, 6 in each bag. How many bags?" Also divide. 4 Ask which number is missing. That decides the operation.