a) examples 

i) 314, 318 or 302

ii) 154 or 176

iii) 254 or 134

 

Calculation errors that involve a small error, but the answer is very close to the correct solution, and is easily identified for self-correction.

 

Students who have made small errors could re-check their own work, or work with a buddy to share how they solved the questions and their results. This could be followed by using a calculator to check their work. They can then solve similar problems using different numbers, e.g., Packing cherries or Multiplication wheel. Check that students are familiar with their multiplication basic facts, e.g., knowing 4 × 8 = 32 and 4 × 7 = 28 makes 4 × 78 more accessible.

a) examples 

i) 288 or 330

ii) 68 or 97

iii) 286 or 225

Students who cannot work out an answer in the region of the correct answer, may need to explore multiplication problems with smaller numbers, e.g., School garden, Rock wall or Gardening at home; ensuring that their basic facts are visually available to support their calculations can help their accuracy. They could also answer some resources that facilitate the use of simple multiplication strategies, such as doubling and halving: Using doubling and halving and Using doubling and halving II.

Students could also explore a number of simple multiplicative estimation questions, e.g., Estimate: 6 × 32 (180 or 200). Note that estimation multiplication with two 2-digit factors can get quite complex (Curriculum Level 4 or 5).