# Finding Percentage Amounts Using Decimals

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The above 45 gram Chocolate Bar contains 25% Sugar.

How many Grams of Sugar are in this “Kit Kat” bar ?

Using Percentages, we know that Percent means /100, and so we can set up:

Grams of Sugar = ( 25 / 100 ) x 45 = 0.25 x 45 = 11.25 grams of Sugar.

Given that one teaspoon of granulated white sugar is equal to about 4.2 grams, our Kit Kat bar contains nearly three teaspoons of sugar.

Thanks to the Sugar, the chocolate bar tastes great, but each gram of sugar contains about 4 calories.

So to burn off the sugar in our Kit Kat bar we would need to burn off 4 x 11.25 = 45 calories.

In terms of Physical Exercise, a person of average weight would need to either skip for 3 minutes, or ride a bike at a fast speed for 3 minutes, or go jogging for 3 minutes to burn off these calories.

A great website for checking out how much sugar is in Food and Drinks is the following:

http://www.sugarstacks.com/

In this lesson we look at Finding the Percentage Amounts of items using Decimals and a Calculator.

The important thing to remember is that we are doing multiplication in these questions, and that “Percent” means divide by 100 or /100.

Steps for Finding Percentage Amount

To use Percentage to Find an Amount:

– Divide the Percentage by 100 to make a Decimal

– Multiply this Decimal by the Amount given

– Do NOT put a % sign on the answer.

Image Copyright 2012 by Passy’s World

Finding Percentage Amount Examples

The following examples show how to work out Percentage Amounts by first converting the Percentage to a Decimal.

Image Copyright 2012 by Passy’s World

Videos on Finding Amount Using Percentage

This video shows how to convert the % to a decimal, and then multiply by the number to obtain the answer.

Here is a video which shows some clever short cuts for calculating Percentage Amounts.

Percentage of a Number – Balloon Invaders

This game is like a Space Invaders type game to play, and is really fun.

Use the arrow keys to move the shooter, and space bar to shoot.

Click the link below to play this game.

Percentages Mystery Game

This game is a movie mystery story with percentage puzzles along the way. Requires sound to hear the story.
Very well produced and entertaining.
Note that you need to mouse over area names on the map to find out how many squares they actually are.

Click the link below to play this game.

http://www.bbc.co.uk/bitesize/ks2/maths/number/percentages/play/popup.shtml

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