There are various methods of subtraction. One method is to use a diagram showing what you start with, what you are taking away, and what you are left with. For example, the problem 5 - 3 might be described with this diagram: Another method to describe and aid in subtraction is to use a number line.
Unit Rates A rate is a ratio that is used to compare different kinds of quantities. A unit rate describes how many units of the first type of quantity corresponds to one unit of the second type of quantity. Some common unit rates are miles (or kilometers) per hour, cost per item, earnings per week, etc. In each case the first quantity is related to 1 unit of the second quantity. Return to Top.
Electricity unit rates and charges. A 'Unit' of Electricity: One unit of electricity is exactly equal to 1000 Watts of power used for 1 hour. When entering a figure in the price per unit above, ensure it is in pence, i.e: '12.710' would be 12.71 pence. If you're not sure on the figure you can find it on your bill or just leave the figure as it is.