AC9M5N06 Year 5 Mathematics

Content descriptor solve problems involving multiplication of larger numbers by one- or two-digit numbers, choosing efficient calculation strategies and using digital tools where appropriate; check the reasonableness of answers

Elaborations

• • Elaboration solving multiplication problems such as 253 \times 4 using a doubling strategy; for example, 2 \times 253 = 506 and 2 \times 506 = 1012
• • Elaboration solving multiplication problems like 15 \times 16 by thinking of factors of both numbers, 15 = 3 \times 5, 16 = 2 \times 8; rearranging the factors to make the calculation easier, 5 \times 2 = 10, 3 \times 8 = 24 and 10 \times 24 = 240
• • Elaboration using an array to show place value partitioning to solve multiplication, such as 324 \times 8, thinking 300 \times 8 = 2400, 20 \times 8 = 160, 4 \times 8 = 32 then adding the parts, 2400 + 160 + 32 = 2592 ; connecting the parts of the array to a standard written algorithm
• • Elaboration using different strategies used to multiply numbers, explaining how they work and if they have any limitations; for example, discussing how the Japanese visual method for multiplication is not effective for multiplying larger numbers