Year 5 Maths Challenge 2 12.1.21

Counting in hundredths…

LO: Find fractions of amounts.

Success Criteria:

Dexter has used a bar model and counter to find ¼ of 12.

Did your bar model look something like this?

Amir uses a bar model and counters to find one quarter of 84.

84

Amir uses a bar model and counters to find one quarter of 84.

84

Which operation are we using when finding a fraction of an amount?

How do we know how many equal groups do we need? Which part of the fraction tells us this?

How does the bar model help us?

Which operation are we using when finding a fraction of an amount?

DIVIDING How do we know how many equal groups do we need? Which part of the fraction tells us this?

DENOMINATOR How does the bar model help us?

HELPS TO VISUALISE AND CHECK WE HAVE EQUAL GROUPS

Find: a) 1/3 of 36 b) 1/3 of 45 c) 1/5 of 65

LO: Find fractions of amounts.

Success Criteria:

LO: Find fractions of amounts.

Success Criteria:  Divide by the denominator.  Multiply by the numerator.

e.g. to find 5/6 of 12 1. Divide by the denominator 12÷6=2 2. Multiply by the numerator 2x5=10 So: 5/6 of 12 = 10.

Find: a) 2/3 of 18 b) 3/5 of 65 c) 7/9 of 18

Success Criteria:  Divide by the denominator.  Multiply by the numerator.

e.g. to find 5/6 of 12 1. Divide by the denominator 12÷6=2 2. Multiply by the numerator 2x5=10 So: 5/6 of 12 = 10.

Extension: Whitney eats 3/8 of 240g bar of chocolate.

How many grams of chocolate has she eaten?

Plenary True or False?

To find 3/8 of a number, divide by 3 and multiply by 8.

Convince me!

Plenary True or False?

To find 3/8 of a number, divide by 3 and multiply by 8.

Convince me!

ANSWERS: Counting in hundredths…

ANSWERS: Find: a) 1/3 of 36 = 12 b) 1/3 of 45 = 15 c) 1/5 of 65 = 13

ANSWERS: Find: a) 2/3 of 18 = 12 b) 3/5 of 65 = 39 c) 7/9 of 18 = 14