The document discusses how to calculate percentage increases and decreases using the formula: Old x (1 ± %). It provides an example of calculating a 30% decrease on a price of $750. It then lists 4 problems: increasing 40 by 70%, increasing 320 by 24%, decreasing 990 by 65%, and decreasing 680 by 11%. It shows the work for calculating each using the percentage formula.

1. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New

2. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%

3. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?

4. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New

5. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original

6. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original
$525.00 = New

7. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original
$525.00 = New
1. Increase 40 by 70% 2. Increase 320 by 24%
3. Decrease 990 by 65% 4. Decrease 680 by 11%

8. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original
$525.00 = New
1. Increase 40 by 70% 2. Increase 320 by 24%
3. Decrease 990 by 65% 4. Decrease 680 by 11%
Old x (1 ± %) = New
40 x (1 + 0.70) = New
68 = New

9. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original
$525.00 = New
1. Increase 40 by 70% 2. Increase 320 by 24%
3. Decrease 990 by 65% 4. Decrease 680 by 11%
Old x (1 ± %) = New
40 x (1 + 0.70) = New
68 = New
Old x (1 ± %) = New
320 x (1 + 0.24) = New
396.8 = New

10. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original
$525.00 = New
1. Increase 40 by 70% 2. Increase 320 by 24%
3. Decrease 990 by 65% 4. Decrease 680 by 11%
Old x (1 ± %) = New
40 x (1 + 0.70) = New
68 = New
Old x (1 ± %) = New
320 x (1 + 0.24) = New
396.8 = New
Old x (1 ± %) = New
990 x (1 - 0.65) = New
346.5 = New

11. Increase/Decrease by a %
We learn the one step method. Formula - Old x (1 ± %) = New
So if we are given a problems saying the sale is 25% off. We are really doing a
calculation to find 75%. Because 100% - 25% is 75%
e.g. The price of the surfboard is usually $750, but the shop is having a 30%
sale. How much will the board actually be sold for?
Old x (1 ± %) = New
750 x (1 – 0.30) = New
750 x (1 – 0.30) = New
750 x 0.70 = New Finding 70% of the original
$525.00 = New
1. Increase 40 by 70% 2. Increase 320 by 24%
3. Decrease 990 by 65% 4. Decrease 680 by 11%
Old x (1 ± %) = New
40 x (1 + 0.70) = New
68 = New
Old x (1 ± %) = New
320 x (1 + 0.24) = New
396.8 = New
Old x (1 ± %) = New
990 x (1 - 0.65) = New
346.5 = New
Old x (1 ± %) = New
680 x (1 - 0.11) = New
605.2 = New