Grade 3 · Maths · Lessons
Stories with groups and arrays
🍪cookies🍽️plates🎀ribbon📖story
Stories with groups.The big ideaEqual groups, all together: multiply. Share it out, or measure it out: divide.
How it works
Equal groups, all together: multiply.
Share it out, or measure it out: divide.
Find what is missing: the total, the number of groups or the size of each.
Example 1: How many plates?
- Maya has 20 cookies. She puts 2 cookies on each plate. How many plates does she fill?
- There are 20 cookies and 2 on each plate.
- Divide: how many 2s in 20?
- So the answer is 10.
Example 2: How many tiles?
- Leo's line of tiles is 21 inches long. Each tile is 3 inches long. How many tiles are in the line?
- The line is 21 inches. Each tile is 3 inches.
- Divide: how many 3s in 21?
- So the answer is 7.
Example 3: How many inches?
- Zoe cuts 7 pieces of ribbon. Each piece is 5 inches long. How many inches of ribbon is that in all?
- 7 pieces, each 5 inches.
- Multiply: 7 groups of 5.
- So the answer is 35.
Words to know
- equal groups
- Groups with the same number in each.
- total
- All together.
Watch out
- Ask: do I know the total, the groups or each?
- Total missing: multiply.
- A group or each missing: divide.
Try it
- Leo's line of tiles is 63 inches long. Each tile is 7 inches long. How many tiles are in the line?
- Leo lays 4 tiles in a line. Each tile is 10 inches long. How many inches long is the line? Which number sentence tells it?
- Leo has 70 tiles for the floor. He lays them in 10 equal rows. How many tiles are in each row? Which number sentence tells it?
Answers: 1. 9 · 2. 4 × 10 = ? · 3. 70 ÷ 10 = ?
For grown-upsMake up stories about snacks: '6 bags with 4 apples each'.