Revision sheet · Mathematics

Numbers and fractions

Adding two fractions: $\frac{a}{b} + \frac{c}{d} = \frac{a d + b c}{b d}$
Dividing by a fraction: $\frac{a}{b} \div \frac{c}{d} = \frac{a d}{b c}$
A number halfway between two numbers: $m = \frac{a + b}{2}$
A repeating decimal as a fraction: $x = \frac{N}{1 0 ^{n} - 1}$
HCF × LCM = the product of two numbers: $L = \frac{ab}{H}$