1. Careless Mistakes The most common mistakes 8 + 19 = 26 (27) 106 2= 58 (53) 7 x 6 = 58 (42) Changing of signs Reading of questions . .

2. Congruence and Similarity Changing the subject of a formula = a = (b) b = a x a c b d c d d c

3. Algebra Factorisation = Over-factorisation -x 2 y – xy + 6 = 6 – xy (x+1) In simplifying into eqns Include “(shown)” Equation and Expression Form an expression (x + y) km Form an equation x + y = 7 Incorrect rejection = 0 (do not reject) is not possible. (rejected) 16d 4d 4abc abc 0 a a 0

4. Simultaneous Linear Equations Write out the equations [ ? (1) ] Change subject [ From (1) : ? ] Substitution [ Sub. x = ? into only (2) ] Complete Equation Reject accordingly [ if necessary ] Substitution [ Sub. y = ? into (1) or (2) ]

6. Volume and Surface Area Open cones and pyramids Bases are not counted in the calculation of surface area. Do not simplify explicit numbers ( like surds and calculations with ) unless asked to. Remember to include units.