maths revi

Apuntes

Year 9 Revision Guide • Percentages Know how to convert between percentages, decimals, and fractions. Compare two different proportions using a percentage. Express one quantity as a percentage of another. Calculate percentages of quantities. Increase and decrease quantities by given percentages. Use multipliers to adjust quantities by percentages. Calculate percentage increases and decreases between two quantities. Find the original quantity after successive percentage changes using multipliers. • Ratio & Direct Proportion Understand the difference between ratio and proportion. Express ratios in words and notation. Write equivalent ratios. Simplify ratios. Compare the relative sizes of two quantities with different units using ratios in the form 1:n or n:1. Calculate unknown quantities given a ratio. Express ratios as 1:n and n:1, including for maps. Share totals using a ratio. Convert between lengths and areas on maps and real-life measurements. Find missing quantities in practical problems involving direct proportionality, including cases with more than two quantities and unit conversions. • Algebraic Expressions Know different ways of wri...