Page 197 - NUMINO TG_3A
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Activity 2 Speed Multiplication
jOb ective Multiply three numbers by using Associative Property of Multiplication.
1. Textbook Instructions Activity 2 Speed Multiplication
Have students learn how to solve 1 . Kate and Thomas pick 3 number cards. They want to multiply the
multiplication problems using Associative
Property of Multiplication. 3 numbers.
1. After students have understood that the I will calculate 7 6 first I will calculate 6 5 first
order in which the numbers are multiplied and then multiply by 5. and then multiply by 7.
does not change the product, have them 7 6 5= ? 6 5 7= ?
learn how to multiply quickly three numbers.
Kate and Thomas want to change the Who will multiply the 3 numbers faster? Explain why.
order in which the three numbers are
multiplied. Have students think about which order would be faster for them to multiply.
In which order did Kate multiply the three Thomas might multiply the 3 numbers faster since 30 is easier to multiply by than 42.
numbers? She calculated the numbers in the
following order: 7 6 5. 112
In which order did Thomas multiply the
three numbers? He calculated the numbers
in the following order: 6 5 7.
How do their products differ? They are the
same.
Whose way of multiplying the numbers is
quicker to calculate? Thomas.
Why? Thomas calculated 6 5 first. After, it
was easier for him to calculate 30 7.
Yes, that’s right. You don’t need to
multiply the numbers in the order they are
written. Therefore, knowing that the order
in which the numbers are multiplied does
not change the product, you can multiply
any of the numbers first to get a quick
answer.
2. Build Understanding
The Order of Three Numbers
You can find Commutative Property of Multiplication and Associative Property of Multiplication in
multiplication of three numbers. Have students find the order in which they multiply the numbers to get a
quick answer. For example, you can change the order of 2 7 5 to 2 5 7. You would be able to
calculate
2 5 7 10 7 much faster than calculating 2 7 5 14 5.
180 NUMINO Teacher s Guide
jOb ective Multiply three numbers by using Associative Property of Multiplication.
1. Textbook Instructions Activity 2 Speed Multiplication
Have students learn how to solve 1 . Kate and Thomas pick 3 number cards. They want to multiply the
multiplication problems using Associative
Property of Multiplication. 3 numbers.
1. After students have understood that the I will calculate 7 6 first I will calculate 6 5 first
order in which the numbers are multiplied and then multiply by 5. and then multiply by 7.
does not change the product, have them 7 6 5= ? 6 5 7= ?
learn how to multiply quickly three numbers.
Kate and Thomas want to change the Who will multiply the 3 numbers faster? Explain why.
order in which the three numbers are
multiplied. Have students think about which order would be faster for them to multiply.
In which order did Kate multiply the three Thomas might multiply the 3 numbers faster since 30 is easier to multiply by than 42.
numbers? She calculated the numbers in the
following order: 7 6 5. 112
In which order did Thomas multiply the
three numbers? He calculated the numbers
in the following order: 6 5 7.
How do their products differ? They are the
same.
Whose way of multiplying the numbers is
quicker to calculate? Thomas.
Why? Thomas calculated 6 5 first. After, it
was easier for him to calculate 30 7.
Yes, that’s right. You don’t need to
multiply the numbers in the order they are
written. Therefore, knowing that the order
in which the numbers are multiplied does
not change the product, you can multiply
any of the numbers first to get a quick
answer.
2. Build Understanding
The Order of Three Numbers
You can find Commutative Property of Multiplication and Associative Property of Multiplication in
multiplication of three numbers. Have students find the order in which they multiply the numbers to get a
quick answer. For example, you can change the order of 2 7 5 to 2 5 7. You would be able to
calculate
2 5 7 10 7 much faster than calculating 2 7 5 14 5.
180 NUMINO Teacher s Guide
