 In this video, we're going to look at percentage increases and percentage decreases using multipliers. You should already know what percentages are, but if you're unsure, watch that video first. We could find a percentage decrease like this by finding the amount and then subtracting it from the original. But there is a much faster way, especially if you have a calculator to hand. It's using multipliers. Multipliers are based on decimals with a slight difference for if you're doing a percentage increase or if you're doing a percentage decrease. Let's start with percentage increases. Can you see how we find the multipliers for percentage increases? Work out the missing multipliers in the table on the right. Pause the video and have a think. Did you get them right? The multipliers for percentage increases are always 1.0 if they're for a 0-100% increase. A 100% increase actually means double and will be a 2.0 multiplier. But what are multipliers? Why are they 1.0? Well, we start with 100% of the item. And then if we want to increase it by 25%, we have the starting 100% plus the increased 25%, so that now we have 125%, which written as a decimal is 1.25. The 1 represents our starting amount and the 0.25 represents the percentage increase. But what happens with percentage decrease multipliers? Pause the video and find the missing values. How did you get on? For percentage decrease multipliers, we need to subtract the percentage from our starting 100% and then turn it into a decimal. So 100 take away 8 is 92%, which as a decimal is 0.92. Now that we know how to find multipliers, let's use them to find percentage increase and percentage decreases. Back to our train ticket example. This is a percentage decrease question. So the multiplier is 100 minus 20, which is 80, and as a decimal, it's 0.8. So 40 multiplied by 0.8 equals 32. See how quick and easy these calculations are? Give these questions a go. Be careful to check if it's asking for an increase or a decrease. Pause the video, work them out and click play when you're ready. So there we have using multipliers to find percentage increases and percentage decreases. For increases, just remember to add 100%. And for decreases, you subtract from 100%.