Formulas and rules
Every key math formula and rule, organised by topic and school level, with examples and study tips.
Numbers 3
M2
Negative numbers
-a + b = b - a
Numbers below zero are negative. Adding a negative moves left, subtracting a negative moves right.
M2
Order of operations (BIDMAS)
Brackets, Indices, Division/Multiplication, Addition/Subtraction
Work through brackets first, then powers, then multiplication and division left to right, then addition and subtraction.
M2
Rounding
Look at the digit after the place you round to: 5 or more rounds up, less than 5 rounds down.