GCSE Maths Decimals, Rounding and Estimation: lesson and practice questions

By the end of this chapter you will be able to

• Use place value to read, write, compare and order decimals
• Add, subtract, multiply and divide decimals using formal written methods
• Change terminating decimals into fractions and fractions into decimals
• Round to a number of decimal places or significant figures, and truncate
• Estimate by rounding to 1 significant figure and use estimates to check answers
• Write error intervals for rounded and truncated numbers and use limits of accuracy
• (Higher) Find upper and lower bounds of calculations

You should already know

• Place value and the four operations with whole numbers (Chapter 1)
• Multiplying and dividing by 10, 100 and 1000
• Simplifying fractions (Chapter 3)
• Rounding whole numbers to the nearest 10 or 100

Where this leads

• Percentages (Chapter 5)
• Standard form (Chapter 6)
• Substituting into formulae (Chapter 8)
• Compound measures (Chapter 16)
• Accuracy of answers in trigonometry (Chapter 20)