# Maths KS1 & KS2: How long is half an hour?

Sabrina’s meeting an Olympic swimmer – who is half an hour late. The children give examples of things in their daily lives that take just half an hour – such as music lessons.

They also remember that half an hour is the same as 30 minutes.

Tempo helps Sabrina find half an hour later on a clock face by folding the clock in half.

Sabrina meets the athlete, and finds out she can swim around 120 lengths in half an hour.

Sabrina works out this is four lengths a minute – and that each length takes her just 15 seconds.

From BBC Series Round the Clock.

### Teacher Notes

KS1:

Explore half by finding half of: different shapes (including a circle), 60 counters (sharing equally between two plates or a 60 number line (by folding a piece of paper in half).

Help children to recognise that half means into two equal parts. Find out how many ways they can fold a circle in half.

As a practical activity, ask children to turn all the way round and then turn half way round or move the minute hand on a clock half way round starting at 12.

Can they move the minute hand half an hour starting from different numbers?

KS2:

How many different ways can you find half a 4 x 4 square?

Help children to recognise that half means two equal amounts that do not have to be congruent.

Show how the minute hand moves half way round the clock to show half past. Hide the minute hand and just look at the hour hand. Move the hour hand half way between 4 and 5, and ask children to estimate the time

Children could challenge each other to estimate the time using only the hour hand.

Encourage the use of vocabulary such as past 4 o’clock, half way, half past, before 5 o’clock etc.