Faded examples · Increasing an amount by a percentage (multiplier method)
Each example shows a little less than the one before – complete the faded steps yourself, using the same two steps every time: write the multiplier, then multiply. Also answer the check question.
①Example 1fully worked: read it through
Increase $40$ by $20\%$.
1Multiplier $=1+\dfrac{p}{100}$
multiplier $=1+0.20=1.2$
2Multiply the amount by it
$40\times1.2=48$
Check · Why is the multiplier $1.2$ and not $0.2$?A you keep the original $100\%$ AND add $20\%$, so $120\%=1.2$B because $20\%=1.2$C a mistake – it should be $0.2$D because $40$ is even
②Example 2fully worked: read it through
Increase $60$ by $15\%$.
1Multiplier $=1+\dfrac{p}{100}$
multiplier $=1+0.15=1.15$
2Multiply the amount by it
$60\times1.15=69$
Check · What multiplier would DECREASE by $15\%$ instead?A $1.15$B $0.85$C $0.15$D $1.5$
③Example 3you finish the last 1 step
Increase $200$ by $8\%$.
1Multiplier $=1+\dfrac{p}{100}$
multiplier $=1.08$
2Multiply the amount by it
$200\times1.08=216$
Check · What is $8\%$ written as part of the multiplier?A $0.8$B $0.08$C $8.0$D $1.8$
④Example 4your turn: every step
Increase $45$ by $40\%$.
1Multiplier $=1+\dfrac{p}{100}$
multiplier $=1.4$
2Multiply the amount by it
$45\times1.4=63$
Check · To go back from $63$ to $45$ you would...A divide $63$ by $1.4$B divide $63$ by $0.4$C multiply by $1.4$D subtract $40$
mathedup.co.uk · sheet 5UEE