reverse percentages: a visual approach

Percentages:a visual approach

0 10 20 30 40 50 60 70 80 90 100

£200

0 10 20 30 40 50 60 70 80 90 100

£200 ???

0 10 20 30 40 50 60 70 80 90 100

£200 ???

???

0 10 20 30 40 50 60 70 80 90 100

£200 ???

???

How did you work it out?

0 10 20 30 40 50 60 70 80 90 100

£200 ???

???

How did you work it out?

Write down the steps in detail

0 10 20 30 40 50 60 70 80 90 100

£200 ???

???

How did you work it out?

Write down the steps in detailTry the next one…

The next problem…

0 10 20 30 40 50 60 70 80 90 100

£140

0 10 20 30 40 50 60 70 80 90 100

£140 ???

0 10 20 30 40 50 60 70 80 90 100

£140 ???

???

It gets better …

0 10 20 30 40 50 60 70 80 90 100 110 120

£180

0 10 20 30 40 50 60 70 80 90 100 110 120

£180

???

0 10 20 30 40 50 60 70 80 90 100 110 120

£180

??? ???

Another one…

0 10 20 30 40 50 60 70 80 90 100 110 120

£352.50

£???

0 10 20 30 40 50 60 70 80 90 100 110 120

£352.50

£??? £???

There’s more…

A laptop is marked as 10% off in a sale. The price is £540. What was the original cost of the laptop?

0 10 20 30 40 50 60 70 80 90 100

£540

A laptop is marked as 10% off in a sale. The sale price is £540. What was the original cost of the laptop?

0 10 20 30 40 50 60 70 80 90 100

£540

A laptop is marked as 10% off in a sale. The sale price is £540. What was the original cost of the laptop?

£???

The last one…

Algernon has received a 5% pay rise. His new wages are £18 275. What were Algernon’s wages before the pay rise?

0 10 20 30 40 50 60 70 80 90 100 110 120

£18 275

???