Lesson

When we want to find the difference between two numbers, we need to construct a subtraction number sentence and use any of the strategies you have learnt to solve it.

For example, if we wanted to know the difference between $43$43 and $17$17, we could write this as: $43-17=26$43−17=26. We can also solve problems with decimals, such as the difference between $4.12$4.12 and $10.45$10.45 can be written as $10.45-4.12=6.33$10.45−4.12=6.33.

We can also find the difference between times in a similar way but it's important to remember that there are $60$60 minutes in an hour so we have to adjust our counting accordingly. People often forgot this in the calculations which can lead to errors. For example, the difference between $6$6 p.m. and $5:30$5:30 p.m. is $30$30 minutes. This is **NOT** the same as $6-5.3$6−5.3 which people commonly (and mistakenly) write as $0.7$0.7 or $70$70 minutes.

Remember!

$60$60 minutes makes $1$1 hour

Find the value of

$11$11 hours $-$− $43$43 minutes

$\editable{}$ hours $\editable{}$ minutes

Find the value of

$2$2 hours $50$50 minutes $+$+ $3$3 hours $40$40 minutes

$\editable{}$ hours $\editable{}$ minutes

A short film clip started to be played at $8$8:$26$26 AM and finished at $8$8:$27$27 AM. How long is the film clip?

$\editable{}$ minute(s)

Estimate and determine elapsed time, with and without using a time line, given the durations of events expressed in minutes, hours, days, weeks, months, or years