Home | Lesson Archive | Year 3 Maths Archive | L2: Singapore's otters

Fractions of quantities: L2: Singapore's otters

3 - Whiteboard Challenges

Agree or disagree?

This photograph shows 1/4 of a different group of otters, who also like to hang out together in Singapore.

Emma said, “There must be 24 otters in this particular group.”

Do you agree with Emma? Can you prove your answer by drawing a bar model? 

Did you know?

In the wild, most otters feed on fish and crustaceans. Sometimes, the crafty smooth-coated otters of Singapore will steal expensive fish (such as koi carp) from garden ponds!

Whiteboard Challenges

Divide the bars and use counters to solve the problems below.

In one particular Singapore garden, there were 12 koi carp in a pond.

1) 1/4 of the koi carp in the pond were eaten by smooth-coated otters.

How many koi carp were left in the pond?

2) Of the remaining koi carp, 1/3 were female.

How many male koi carp were left in the pond?

3) In a different pond, 7 fish were eaten by smooth-coated otters.

If the otters ate 1/5 of the total amount of fish in this pond, how many fish were there in the pond to begin with?