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Number Trail Grade 3 / Week 02 / Tuesday
2/6
Week 02 · Multiply: equal groups

Tuesday

Arrays
// Groups, arrays and stories
⏱ about 15 min

Tuesday: Arrays

Chris and Lizzy the Lizard plant seeds in Lizzy's garden.

"Let us plant 3 rows of 5 seeds," says Lizzy.

Chris lines up the seeds with his paw.

"Look, the rows are all the same length," he says.

Lizzy taps her notebook. "That makes it easy to count."

"It is an array," says Chris. "Equal rows, like equal groups."

Learn it: rows and columns

An array has equal rows.

Rows go across. Columns go up and down.

Lizzy's garden has 3 rows with 5 seeds in each row.

Dots in three rows of five

Each row is a group of 5.

We can add: 5 + 5 + 5 = 15.

We can multiply: 3 × 5 = 15.

Bigger arrays work the same way.

This grid has 6 rows of 7 squares.

It shows 6 × 7 = 42.

A rectangle of unit squares, six rows of seven
COUNT THE ROWS
  • Read the question.
  • Tap your answer.
Dots in three rows of fiveHow many rows does this array have?
Dots in four rows of twoHow many rows does this array have?
Dots in five rows of fourHow many rows does this array have?
A rectangle of unit squares, six rows of sevenHow many rows does this array have?
MATCH THE ARRAY
  • Read the question.
  • Tap your answer.
Dots in three rows of fiveWhich multiplication matches the picture?
Dots in four rows of twoWhich multiplication matches the picture?
Dots in five rows of fourWhich multiplication matches the picture?
A rectangle of unit squares, seven rows of eightWhich multiplication matches the picture?
FIND THE PRODUCT
  • Read the question.
  • Tap your answer.
Dots in four rows of two4 × 2 = ?
Dots in five rows of four5 × 4 = ?
A rectangle of unit squares, six rows of seven6 × 7 = ?
A rectangle of unit squares, eight rows of five8 × 5 = ?
GARDEN ARRAYS
  • Read the question.
  • Tap your answer.
A seedLizzy plants 3 rows of 9 bean seeds. How many seeds?
A potChris sets 5 rows of 5 flower pots. How many pots?
A berryA berry patch has 4 rows of 7 plants. How many plants?
A sproutThere are 2 rows of 10 sprouts. How many sprouts?
SentenceTrue or false?
3 × 5 = 15?
6 × 7 = 44?
4 × 7 = 28?
8 × 5 = 35?
WHY THIS EXERCISE6 × 7 = 42, and 8 × 5 = 40.
Try it
Find an egg carton or a muffin tin at home.
Count the rows. Then count the cups in one row.
Say the multiplication, like "2 rows of 6."
Find the product.
◇ BUILD ARRAYS WITH A GROWN-UP
Your grown-up says a multiplication, like 3 × 4.
You build it with spoons or blocks in rows.
Count to check the product together.
Switch jobs and build three more arrays.

Amazing arrays! Tomorrow we hop and measure with multiplication.

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