Comments of sample of informal multiplication This page briefly explains the mental methods used by the different children and classifies the methods using the scheme discussed in 'Mental methods for subtraction'. Some methods may display characteristics of more than one of the classifications. Back to 'top' of Classification activity Belinda Belinda uses multiplication by rounding. Belinda thinks of 38 as 40 - 2. This gives Belinda two easier calculation to solve. Back to Classification activity Ben Ben uses front end multiplication. He multiplies by the hundreds then the tens then the ones. He then adds the partial products to get the final result. Back to Classification activity Craig Craig first uses multiplication in stages (using factors) and breaks 16 into 4x4. He then use multiplication by rounding (using the distributive property). Back to Classification activity Greg Greg uses repeated addition. Although he is easily able to find the answer in this situation, calculations with larger numbers will be difficult to solve this way. Back to Classification activity Karim Karim uses front end multiplication. Karim first multiplies by the tens and then the ones. The partial products are then added to get the final result. Back to Classification activity Lara Lara uses multiplication by halving and doubling. She halves 8 and doubles 15 to reduce to a known fact. Back to Classification activity Lisa Lisa uses multiplication by halving and doubling. She first halves 28 twice to get 7 and doubles 25 twice to get 100. By doing this the calculation is reduced to a simple known fact. Back to Classification activity Samantha Samantha uses a combination of three strategies. She first uses multiplication by halving and doubling. She then use multiplication by rounding (using the distributive property) and sees 14 as 10 + 4, giving her a know fact of 10 x 112 to solve. To complete the problem, Samantha finally uses front end multiplication. Samantha has good number sense but her method is quite tedious and she could benefit from being shown the more direct formal algorithm. However, she does display fantastically good mental gymnastics. Back to Classification activity Simon Simon uses multiplication by rounding and sees 97 as 100-3. This leaves Simon to solve two simple known facts. Back to Classification activity Tania Tania uses multiplication by rounding seeing 103 as 100+3. She then solves the two known facts and adds these partial products to get the result. Back to Classification activity