Mathematics · Year 1

Active learning ideas

Halving Even Numbers to 20

Active learning lets children feel and see the equal split of even numbers, turning an abstract idea into a concrete experience. When students manipulate objects, they build mental images of halving that support later fraction and division work.

• National Curriculum Attainment Targets
• KS1: Mathematics - Multiplication and Division
• KS1: Mathematics - Fractions

• 15–30 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Stations Rotation
• 25 min · Pairs

Pairs: Counter Sharing Challenge

Give pairs bags of 12, 16, or 20 counters. They share into two bowls equally, draw the halves, and label with numbers. Pairs then explain their method for 16 to the class. Extend by inventing a story for the counters.

Compare halving numbers to 10 with halving numbers to 20.

Facilitation Tip

During Pairs: Counter Sharing Challenge, move between pairs to listen for reasoning, not just the final split, so you can address misconceptions on the spot.

What to look for

Give each student 16 counters. Ask them to physically divide the counters into two equal groups and record how many are in each group. Then, ask them to write the number sentence: 16 divided by 2 equals 8.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 02

• Stations Rotation
• 30 min · Small Groups

Small Groups: Cube Tower Halving

Groups build towers with even cubes up to 20, then snap or separate into two equal towers. Record the original and halves on charts. Compare towers to 10 with those to 20, noting doubled sizes.

Construct a method to halve the number 16.

Facilitation Tip

For Small Groups: Cube Tower Halving, ask each group to demonstrate their method to the class so students compare different strategies side by side.

What to look for

Present students with the numbers 15 and 14. Ask: 'Which of these numbers can we share into two perfectly equal whole number groups? How do you know?' Encourage them to use the terms 'even' and 'odd' in their explanations.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 03

• Stations Rotation
• 20 min · Whole Class

Whole Class: Even Number Line-Up

Students hold numeral cards 10-20. Call even numbers; holders pair up and halve by sharing counters between them. Class discusses why odds stay out and justifies the rule.

Justify why only even numbers can be halved into two equal whole numbers.

Facilitation Tip

In Whole Class: Even Number Line-Up, invite students to place their halved numbers on a washing line to show the pattern of halves from 2 to 20.

What to look for

On a small card, write the number 18. Ask students to draw a picture showing how they would halve this number using objects, and then write the answer to 'What is half of 18?'

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 04

• Stations Rotation
• 15 min · Individual

Individual: Bead String Split

Each child threads even beads up to 20 on strings, folds to find halves, and records pairs. They mark even vs odd attempts to see patterns.

Compare halving numbers to 10 with halving numbers to 20.

What to look for

Give each student 16 counters. Ask them to physically divide the counters into two equal groups and record how many are in each group. Then, ask them to write the number sentence: 16 divided by 2 equals 8.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

A few notes on teaching this unit

Teachers should avoid rushing to abstract symbols before concrete experience; use manipulatives to build the concept first. Research suggests that young children learn division best when they physically act out the sharing process and discuss their actions. Build in frequent pauses to compare halves of smaller numbers with teens so children notice the doubling link.

Successful learners will confidently partition even totals into two equal groups, explain why only even numbers work, and connect halving to doubling facts by the end of the activities. They will use terms like ‘half’ and ‘equal’ with growing accuracy.

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Watch Out for These Misconceptions

• During Pairs: Counter Sharing Challenge, watch for students who claim any number can be halved equally.

  Prompt them to try with an odd number like 9, leaving one counter aside, and ask them to explain what happened when the groups weren’t equal.

• During Small Groups: Cube Tower Halving, watch for students who halve 16 by rote-counting back from 1 instead of physically splitting the tower.

  Have them rebuild the tower and physically break it into two equal parts, counting each part aloud to connect the action with the number sentence.

• During Whole Class: Even Number Line-Up, watch for students who believe numbers over 10 cannot be halved the same way.

  Ask them to compare their halved answers for 10 and 20, noticing that 20 is double 10 and its half is double 5, building the pattern together.

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Methods used in this brief

• Stations Rotation