Using Mental Math Strategies:
Multiplication & division Facts
N4 Explain the properties of 0 and 1 for multiplication and the property of 1 for division
N5 Describe and apply mental mathematics strategies, such as:
N5 Describe and apply mental mathematics strategies, such as:
- skip counting from a known fact
- using doubling or halving
- using doubling or halving and adding or subtracting one more group
- using patterns in the 9s facts to determine basic multiplication facts to 9 × 9 and related division facts
A magic pot returns three times as many things as you put into it. For example, if you put in one coin, three coins come out. What are some total numbers of coins between 30 and 40 you could end up with? What are some you could not end up with. Explain your thinking.
Stretch Your Thinking
How does knowing that 4 x 6 = 24 help you solve other multiplication questions?
A bus holds 48 students. Think about how you would calculate the number of students on 4 buses and on 9 buses using mental math. Would you use the same strategy for both calculations? Explain your thinking.
All stretch questions are from Open Questions for Rich Math Lessons (Number Strand) by Marian Small