Remember to multiply by 100, we move each digit in the number two places left, whilst keeping the decimal point fixed in place. However, it is important to multiply smaller decimals by 100 carefully. We simply wrote the 4 and the 3 in 0.43 as 43%. It is easier to do mentally because we are only moving a single point rather than moving each digit.Īgain, moving the decimal point two places right, we can see thatĪ decimal number that has two non-zero decimal digits is written as a percentage by writing both non-zero digits in front of the % sign. Moving the decimal point two places right has the same effect as moving each digit two places left. However, once this process is understood, the most efficient method to teach is the method below, where we only move the decimal point.
When introducing multiplying by 100, it is best to teach it using the method above, as we can see the numbers getting larger. Moving each digit is a longer process than simply moving the decimal point instead. Otherwise, the digits in 0.43 are in the same order as in 43%. Notice that the 0 at the beginning of 0.43 has been removed because we do not write zeros at the start of whole numbers. We move the 4 into the tens column and the 3 into the units column. In the first method, we keep the decimal point in the same place and move each digit in the number two places to the left. We can work out the calculation of 0.43 × 100 using either of the two methods. Or alternatively, move the decimal point two places to the right.īoth methods multiply by 100 by multiplying the number by ten and then multiplying it by 10 again.įor example, to write the decimal 0.43 as a percentage, we multiply 0.43 by 100 to get 43 and then write a percentage sign afterwards.Move each digit in the number two places to the left, keeping the decimal point in place.To multiply a decimal by 100, use one of the following two methods:
To write a decimal number as a percentage, multiply it by 100 and then write a % sign afterwards.
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