Find the missing numbers here. … … 1 1.7 2.7 4.4 … … Mental methods N3.1 Extension Starter The rule for this sequence is ‘to get the next number, add the two previous numbers’ Find the missing numbers here. … … 1 1.7 2.7 4.4 … … 0.57 × 7 = 3.99 How can you use this to work out 1.57 × 7 and 10.57 × 7? Find at least three pairs of numbers which fit this expression. 1.7 + … = … + 5.9 Preamble These three independent activities give pupils practice in performing mental calculations with decimals, and also revision of sequences. As is always the case, group discussion will allow pupils to learn from each other as well as giving them practice at explaining their work verbally. Possible content Mental methods of calculation. Resources None. Solution/Notes 0.3 0.7 1 1.7 2.7 4.4 7.1 11.5 1.57  7 = (0.57  7) + 7 = 3.99 + 7 = 10.99 10.57  7 = (0.57  7) + 70 = 3.99 + 70 = 73.99 Any correct numbers fitting 1.7 + … = … + 5.9 (The difference between numbers will always be 4.2.)