# Selecting multiplication facts

Purpose

The purpose of this activity is to support students to select an appropriate multiplication fact to solve a problem with equal sets. By this stage of development should begin committing multiplication facts to memory, especially those related to factors of two, five, and ten.

Achievement Objectives
NA2-1: Use simple additive strategies with whole numbers and fractions.
Required Resource Materials
• Materials to form equal sets, such as cubes, tiles, novelty counters, and play dollar coins.
• Calculators
Activity
1. Pose multiplication problems with basic facts, beginning with factors of two, ten, and five.
Kenese weaves ili (fans) to sell at Matakana market.
She makes four ili each day for five days (Monday to Friday)
How many ili does she take to the market on Saturday?
Let students use objects or draw diagrams, if needed, to represent the problem.
2. Discuss strategies to work out the total number of ili. Record the strategies as equations, such as:
4 + 4 = 8, 8 + 8 = 16, 16 + 4 = 20
5 + 5 + 5 + 5 = 20
I have a calculator. What should I enter to solve Kenese’s problem with multiplication?
You may need to prompt students with questions, like:
How many days does Kenese make ili? (Enter 5)
How many ili does she make each day? (Enter x 4)
How do I get an answer? (Enter =)
Highlight that 4 x 5 = 20 also gives the answer.
3. Pose similar problems with equal groups. Allow students to represent the situations with physical or diagrammatic models, if needed. Permit access to calculators. Ideally, students will progress to using multiplication calculations to solve the problems.
Good examples might be:
• Tipene catches 10 pātiki (flounder) each day to help feed his whānau.
He fishes every day of the week, unless the weather is rough.
How many pātiki does Tipene usually catch each week?
• Sophie collects All Black cards.
Her family eat a packet of weetbix each week and each packet contains three cards.
How many cards will Sophie have at the end of eight weeks?
• Laione walks and feeds his neighbour’s dog for 10 days.
He is paid \$4 each day.ow much does he earn?
• Manu loves kiwifruit. He eats five kiwifruit each day.
How many kiwifruit does he eat in five days?

Next steps

1. Increase the level of abstraction by progressing from materials and diagrams to using equations to represent the problems and calculate answers.
2. Move from asking problems that involve two, five and ten as factors to problems with three, four, six, seven, eight and nine as factors. More complex problems help to ‘sell’ the efficiency of multiplication to students.
3. Build up students’ knowledge of basic multiplication facts.
4. Provide students with multiplication equations and ask them to create word problems that match.