subtracting percentages with a calculator

SUBTRACTING PERCENTAGES WITH A CALCULATOR FULL

50% is the same as a half, so 50% of 10 is 5, because five is half of 10 (10 ÷ 2). We can calculate percentages using this knowledge. To write a percentage as a decimal, simply divide it by 100.įor example, 50% becomes 0.5, 20% becomes 0.2, 1% becomes 0.01 and so on. It can therefore be written as both a decimal and a fraction. In this case, the ‘whole’ is George’s old salary. When you are calculating percentages, the key is to check that you are working with the correct whole. However, his old salary is not 100% of his new one. This example is one: George’s new salary is actually 105% of his old one. It is possible to have percentages over 100%. You now know that the discount is worth £100.Ĭomplete the calculation by adding or subtracting as necessary. Once you have worked out the value of 1%, you simply multiply it by the percentage you are looking for, in this case 20%. Multiply it by the percentage you are looking for

SUBTRACTING PERCENTAGES WITH A CALCULATOR FULL

You are then going to take that off the full price to find out what the laptop will cost you. The percentage that you need to find is 20%, or the discount offered by the supplier. In this example, the whole is £500, or the cost of the laptop before the discount is applied. How much will the laptop cost from that supplier? You have checked local suppliers and one company has offered to give you 20% off the list price of £500.

Let’s suppose that you want to buy a new laptop computer. This is easiest to understand with an example. Work out the value of 1%, then multiply it by the percentage you need to find. The general rule for finding a given percentage of a given whole is: This is partly why so many countries use a metric system of measurement and decimal currency. Importantly, this also makes it much easier to make comparisons between percentages (which all effectively have the common denominator of 100) than it is between fractions with different denominators. It is much simpler to work with parts of 100 than thirds, twelfths and so on, especially because quite a lot of fractions do not have an exact (non-recurring) decimal equivalent. We use percentages to make calculations easier. For example, if there had been 200 cells in the grid, each percentage (1%) would be two cells, and every cell would be half a percent. The answer is that you convert the individual elements that make up the whole into a percentage. It is easy to work out the percentage when there are 100 individual ‘things’ making up the whole, as in the grid above. Again, out of 100 cells, 17 are white, or 17%. There is one red cell, two green, five blue, 25 purple, and 50 yellow. Add up the number of other cells, and take them from 100.Out of 100 cells, 17% are therefore white. How many unshaded (white) cells are there? What is the percentage of unshaded cells?Īnswer: There are two ways to work this out. Understanding Statistical Distributions.Area, Surface Area and Volume Reference Sheet.Simple Transformations of 2-Dimensional Shapes.Polar, Cylindrical and Spherical Coordinates.Introduction to Cartesian Coordinate Systems.Introduction to Geometry: Points, Lines and Planes.Percentage Change | Increase and Decrease.Mental Arithmetic – Basic Mental Maths Hacks.Ordering Mathematical Operations - BODMAS.Common Mathematical Symbols and Terminology.

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Subtracting percentages with a calculator