Stage 7 of 20
Doubling and Halving
Doubling and halving are twin skills. They speed up multiplication, help with even/odd checks, and support fraction sense later.
Use doubles as building blocks
Know doubles to 20 cold (6+6, 7+7…). For near-doubles like 7+8, double the smaller and add 1. Halving even numbers means sharing into two equal groups.
Why this mental math skill matters
Doubles are high-frequency facts. Near doubles and halving connect addition, multiplication, and early fraction sense.
Worked examples
Study each example slowly. Say the steps aloud — verbal rehearsal strengthens mental arithmetic memory.
8 + 8
- Classic double.
- 8 × 2.
- 16.
Answer: 16
7 + 8
- Near double of 7.
- 7 + 7 = 14, then +1.
- 15.
Answer: 15
Half of 36
- Half of 30 is 15.
- Half of 6 is 3.
- 15 + 3 = 18.
Answer: 18
Tips for success
- Learn doubles cold before near doubles.
- Halve tens and ones separately for larger even numbers.
- Use doubling language when you meet ×2 later.
Common mistakes to avoid
- Confusing near-double direction (adding vs subtracting 1).
- Trying to halve odd numbers without a clear remainder plan.
How to practice this stage
Drill doubles to 20, then near doubles, then halves of even numbers. Mix them in one short session.
Interactive practice
Stage 7 Drill
Double or halve the given number.
Solve
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FAQ: Doubling and Halving
How do near doubles work?
For 7 + 8, double 7 to get 14, then add 1 because 8 is one more than 7.
Why practice halving?
Halving supports ÷2, fraction ideas like 1/2, and later percentage shortcuts such as 50%.