Page 194 - NUMINO TG_3A
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12Beat the Calculator! Unit
Objective: Multiply more than 2 numbers using multiplication properties What kind of insect did Ricky think it was?
An ant.
Who do you think is right? Why did Ricky think it was an ant?
An ant has six legs. So, Ricky thought there
I think there are No, I think there are were eight ants.
8 small creatures. 6 small creatures. If an ant has six legs and there are eight
ants, how many legs are there in all?
An ant has 6 legs, A spider has 8 legs, 8 6 48. Therefore, there are 48 legs.
and 8 6 = 48. and 6 8 = 48. What kind of insect did Ann think it was?
A spider.
So, there are So, there are Why did Ann think it was a spider?
8 small creatures. 6 small creatures. A spider has eight legs. So, she thought there
were six spiders.
Explain why. If a spider has eight legs and there are six
spiders, how many legs are there in all?
Both Ricky and Ann can be right. Since we only know that there are 48 legs in all and 48 can 6 8 48. Therefore, there are 48 legs.
be divided by 6 or 8, there can be either 8 ants or 6 spiders. Who is correct?
Possible answer:
Both Ricky and Ann are correct. Since we
only know that there are 48 legs in total, and
48 can be divided by 6 or 8, there can either
be 8 ants or 6 spiders.
12. Beat the Calculator! 109
In the next stage, students will learn about Commutative Property of Multiplication. Prepare them for the next
stage by giving them the following task.
Have students find and discuss about multiplication sentences (from 2 to 9 times table), where the products
do not change even though the factors have changed.
Example: 5 4 20, 4 5 20.
6 3 18, 3 6 18.
7 4 28, 4 7 28.
3A Unit 12 177
Objective: Multiply more than 2 numbers using multiplication properties What kind of insect did Ricky think it was?
An ant.
Who do you think is right? Why did Ricky think it was an ant?
An ant has six legs. So, Ricky thought there
I think there are No, I think there are were eight ants.
8 small creatures. 6 small creatures. If an ant has six legs and there are eight
ants, how many legs are there in all?
An ant has 6 legs, A spider has 8 legs, 8 6 48. Therefore, there are 48 legs.
and 8 6 = 48. and 6 8 = 48. What kind of insect did Ann think it was?
A spider.
So, there are So, there are Why did Ann think it was a spider?
8 small creatures. 6 small creatures. A spider has eight legs. So, she thought there
were six spiders.
Explain why. If a spider has eight legs and there are six
spiders, how many legs are there in all?
Both Ricky and Ann can be right. Since we only know that there are 48 legs in all and 48 can 6 8 48. Therefore, there are 48 legs.
be divided by 6 or 8, there can be either 8 ants or 6 spiders. Who is correct?
Possible answer:
Both Ricky and Ann are correct. Since we
only know that there are 48 legs in total, and
48 can be divided by 6 or 8, there can either
be 8 ants or 6 spiders.
12. Beat the Calculator! 109
In the next stage, students will learn about Commutative Property of Multiplication. Prepare them for the next
stage by giving them the following task.
Have students find and discuss about multiplication sentences (from 2 to 9 times table), where the products
do not change even though the factors have changed.
Example: 5 4 20, 4 5 20.
6 3 18, 3 6 18.
7 4 28, 4 7 28.
3A Unit 12 177
