NZ Level 4
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Time Difference I
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$4317=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$10.454.12=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$65.3 which people commonly (and mistakenly) write as $0.7$0.7 or $70$70 minutes.

Remember!

$60$60 minutes makes $1$1 hour

 

Examples

Question 1

Find the value of 

$11$11 hours $-$ $43$43 minutes

  1. $\editable{}$ hours $\editable{}$ minutes

Question 2

Find the value of

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

  1. $\editable{}$ hours $\editable{}$ minutes

Question 3

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?

  1. $\editable{}$ minute(s)

Outcomes

GM4-1

Use appropriate scales, devices, and metric units for length, area, volume and capacity, weight (mass), temperature, angle, and time

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