Year 5 · Decimals and percentages · Summary

Year 5 Decimals and percentages: summary and key words

Part of the Year 5 decimals and percentages chapter. Chapter overview · whole chapter on one page

Chapter summary

Skill	Method
Decimal as a fraction	Digits over 10, 100 or 1,000. The number of decimal places tells you the bottom number. Simplify: 0.36 = 36/100 = 9/25.
Place value	Each place to the right is ten times smaller: tenths, hundredths, thousandths. Use 0 as a place holder: 0.07 is 7 hundredths.
Fraction as a decimal	Make the bottom 10, 100 or 1,000 (scale by a factor). 3/4 = 75/100 = 0.75; 9/20 = 45/100 = 0.45.
Compare and order	Write the numbers with the same number of decimal places, then compare from the left: 0.6 = 0.60 is greater than 0.58.
Round	Look at one digit: the digit after the place you round to. 5 or more: up. 4 or less: down. 3.449 rounds to 3.4 (one decimal place).
Add and subtract	Line up the decimal points, fill empty places with zeros, then calculate column by column from the right.
Per cent	Per cent means out of 100. 35% = 35/100 = 0.35. Multiply a decimal by 100 to get a percentage: 0.8 = 80%.
Fractions, decimals and percentages	Make the bottom number 100 and the top number is the percentage: 2/5 = 40/100 = 40%. Useful: 1/4 = 25%, 1/5 = 20%, 3/4 = 75%.

I can write a decimal with up to three places as a fraction, and simplify it.
I can say what each digit is worth in tenths, hundredths and thousandths.
I can write a fraction with a bottom number of 10, 100 or 1,000 as a decimal.
I can compare and order decimals with up to three decimal places.
I can round a decimal with two decimal places to the nearest whole number and to one decimal place.
I can add and subtract decimals by lining up the decimal points.
I can change between a percentage, a fraction with denominator 100 and a decimal.
I can write fractions such as 1/4, 1/5, 2/5 and 4/5 as percentages and decimals.

Decimal point: The point that separates the whole number part from the tenths, hundredths and thousandths.
Place value: The value of a digit, which depends on its column, such as tenths or hundredths.
Tenth, hundredth, thousandth: One part of 10, 100 or 1,000 equal parts. 0.1 is one tenth, 0.01 is one hundredth.
Place holder: A zero that keeps the other digits in the right columns, such as the 0 in 0.07.
Round: To change a number to the nearest value in a given place.
Halfway number: The number exactly between two numbers. 4.5 is halfway between 4 and 5.
Per cent (%): Out of one hundred. 35% means 35 out of 100.
Equivalent: Having the same value, but written in a different way, such as 1/2, 0.5 and 50%.
Highest common factor (HCF): The biggest number that divides exactly into two or more numbers. Used to simplify fractions.
Column method: A written method for adding or subtracting, with the place values in columns.