Number · Challenge 6 of 25 · about 4 min
Double-Double Multiplication
Multiply by four by doubling twice.
Year 4 challenge progress
0 of 25 complete
1 Read
Your challenge
Four boxes contain 16 markers each. How many markers are there altogether?
Take your time. Your answer is checked only when you choose Check Answer.
Curriculum details
- Curriculum code
- VC2M4N06
- Strand
- Number
- Focus
- Use an efficient mental strategy for multiplication.
2–5 Notice · Build · Move · Connect
Interactive visual
An interactive Double-double model is ready. Choose Show Visual Trick to reveal and hear one mathematical change at a time.
Visual Trick
Double-double
To multiply by 4, double the number and then double it again.
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Step 1
Show four matching groups of 16 markers.
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Step 2
Combine two groups: double 16 to make 32.
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Step 3
Combine the two doubled groups: double 32 to make 64.
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Step 4
Connect the model to 16 × 4 = 64.
6 Solve
Your answer
7 Check
Worked explanation
Why the answer makes sense
- Two groups of 16 make 32.
- Two groups of 32 make 64.
- Doubling twice is multiplication by 4, so 16 × 4 = 64.
Challenge complete
This counts as one completed curriculum item. You can replay the model or review it again anytime.