The associative law states that it doesn't matter how you group or pair values (i.e. which we calculate first), the result is still the same. It applies for addition and multiplication.

A composite number is an integer with more than two factors. All integers greater than 1 are either composite or prime.

Explain how to use the associative law to multiply efficiently

Maths

In this unit pupils will learn to multiply a 3-digit by a 2-digit number They will use accurately short and long division and use a ratio chart to solve short and long division. In the future unit pupils will add, subtract, divide and multiply with integers, decimals, positive and negative values.

In the prior unit pupils will multiply a 3-digit number by a single-digit number using expanded and short multiplication. In this unit pupils will learn why the product stays the same when one factor is doubled and the other is halved and explain the effect on the product when scaling the factors by the same amount. 

Multiplying and dividing by 2-digit numbers

Look at the numbers below and select the prime numbers.

Which of these are ways that 14 could be represented with its factors?

Select the expressions that are equivalent to 23 × 3 × 9

Select the expressions that are equivalent to 24 × 18

Look at the equation. Find the missing number.      29 × 33 = 29 × 3 × {{ }}. 

Look at the long multiplication below, what is the missing partial product?

Select the numbers that are factors of 12

Which of these is the complete list for the factors of 16?

What is the missing factor of 72? 1, 2, 3, 4, 6, 8, 9, 12, {{ }}, 24, 36, 72

Sam and Andeep are estimating the total number of visitors across the 35 Olympic venues on one day. Each venue has on average 6,012 visitors per day. How many visitors on average, visited on this day?

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Explain how to use the associative law to multiply efficiently

Lesson outcome