Using commutativity and associativity to multiply

Using commutativity and associativity to multiply

Lesson details

Key learning points

  1. In this lesson, we will explore the laws of multiplication, and use known facts and the laws of commutativity and associativity to perform efficient multiplication.

Licence

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5 Questions

Q1.
I scored 13, 15 and double 9 on the dart board. What is my total?
37
Correct answer: 46
55
Q2.
I scored 11, triple 6 and double 8 on the dart board. What is my total?
39
Correct answer: 45
51
Q3.
I scored double 2, triple 10 and a bullseye. What is my total?
39
Correct answer: 84
88
Q4.
I have 300 points. I have just deducted 87 points. How many points do I have left?
113
203
Correct answer: 213
Q5.
I have 201 points. I have just deducted 93 points. How many points do I have left?
107
Correct answer: 108
109

5 Questions

Q1.
What is the commutative law in multiplication?
If you change the order of factors and the product will change too.
Correct answer: You can change the order of factors and the product will be the same.
Q2.
What is the associative law in multiplication?
Correct answer: You can multiply more than two factors in any order and the product will be the same.
You can multiply three factors in a certain order.
You should not multiply more than two factors.
Q3.
Which law do you use when multiplying 2 x 5 x 6?
Correct answer: associative law
commutative law
Q4.
When multiplying 6 x 2 x 5, which is the most efficient order?
Multiply 2 by 5 then multiply 10 by 6
Correct answer: Multiply 6 by 5 then double
Multiply 6 x 2 then multiply 12 by 5
Q5.
8 x 4 x 10 = 4 x 10 x 8. True or false?
False
Correct answer: True

Lesson appears in

UnitMaths / Exploring calculation strategies and place value