Math: Decimals & Percentage

• A decimal is a way of writing a number using place values of tenths, hundredths, etc.
• The decimal point separates the whole numbers from the fractional part
• If there are no digits on the left side of the decimal point, then the decimal has zero as its whole-number part
• When multiplying or dividing decimals, line up the decimal points so that they are directly above one another
• When adding or subtracting decimals align the decimal points one under another. If necessary, add a zero/s to the empty spaces to hold the place value
• A fraction can be written as a decimal and vice versa
• A decimal can be shown on a number line. You can use the number line to compare the size of two decimals
• To change a percentage into a decimal, divide it by 100
• To convert a decimal into a percentage, move the decimal point two places to the right and attach % sign at the end.
• Decimals can be written in fraction form. To convert a decimal to a fraction, place the decimal number over its place value. For example, in 0.6, the six is in the tenths place, so we place 6 over 10 to create the equivalent fraction, 6/10. If needed, simplify the fraction.
• This means that all fractions can be converted into decimals by dividing the numerator by the denominator. For example, the fraction 45 represents “4 out of 5,” or 4 divided by 5. This fraction can be converted into a decimal by dividing 4 by 5.