Grade 5 · Math · Unit 4 of 13
Multiply
Multiply up to three digits
What your child practises
Multiplying 2- and 3-digit numbers using area models and partial products, patterns with 10, 100 and 1000, doubling and halving, and estimating products by rounding.
Nunavut Curriculum approved guide: Alberta Mathematics K–9 (2007), Number · multiplying with 1- and 2-digit multipliers
How we explain it
Children can open this short lesson before they practise.
- Break the bigger number into place values.
- Multiply each part, then add the parts together.
- Estimate by rounding to check your answer makes sense.
Example: 23 × 14 = ? 23 × 10 = 230. 23 × 4 = 92. 230 + 92 = 322. Answer: 322
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
A school orders 87 boxes of pencils with 21 pencils in each box. How many pencils is that?
answer boxpencils
1827 pencils
Hint: Equal groups mean multiply. Split one factor into place-value parts, multiply each part, then add.
Question 2
Which has the same product as 45 × 28?
- 45 × 14
- 90 × 28
- 90 × 56
- 90 × 14
90 × 14
Hint: Doubling one factor and halving the other keeps the product the same. Check that only one factor was doubled and the other was halved.
Question 3
Multiply using a pattern.
119 × 100 = ?
answer box
11900
Hint: Multiply the non-zero parts first, then write all the zeros from the factors on the end.
Question 4
Multiply.
176 × 5 = ?
answer box
880
Hint: Split 176 into place-value parts (100 + 70 + 6). Multiply each part by 5, then add the partial products.
Question 5
Which product is the greatest?
- 45 × 17
- 28 × 12
- 54 × 33
- 37 × 39
54 × 33
Hint: Estimate each product with friendly numbers. If two estimates are close, work those out exactly.
Question 6
Use the area model. What is 21 × 29?
Area model for 21 × 29 × 20 1 20 400 20 9 180 9 answer box
609
Hint: Each box holds a partial product. Add all the partial products inside the model to get the total.