Measuring Half Lengths

Overview

In this fourth lesson of the “Sharing Halves and Quarters” unit, students connect the idea of a half with length. They fold paper strips to make equal halves, compare whole and half-lengths, and sequence strips from shortest to longest using mathematical language.

Learning intentions

• WALT use halves when measuring and sequencing objects.
• WALT fold a strip to make two equal halves.
• WALT compare lengths using longer, shorter and the same length.
• WALT explain how we know which objects are shortest and longest.

Success criteria

• I can make a half-length by folding a strip into two equal parts.
• I can compare lengths using longer, shorter or the same length.
• I can sequence objects correctly from shortest to longest.
• I can explain my thinking using whole and half.

Curriculum links

• Mathematics and Statistics: measuring and comparing length using direct comparison and informal units.
• Mathematics and Statistics: recognising and describing halves as two equal parts of a whole.
• Mathematics and Statistics: using mathematical language, representations and explanations to communicate thinking.
• Mathsteasers: developing higher-order thinking through challenges that deepen mathematical understanding.

Lesson structure (60 minutes)

1. 0–7 min · Hook and revisit. Teacher displays a long paper strip and asks, “If we fold this strip into two equal parts, what will each part be called?” Open with the hook and learning intention slides and model the words whole, half, equal, longer and shorter. Students turn and talk, then show with their hands where they think the middle might be.

2. 7–17 min · Teacher modelling. Teacher demonstrates placing the two ends of a strip together, folding carefully, pressing the crease and opening it to reveal two equal half-lengths. Emphasise that a half must be equal, not simply any piece cut from a whole. Use the slides’ picture-supported vocabulary and arrows for ordering. Students rehearse orally: “The strip is a whole. Each part is a half. The two halves are the same length.”

3. 17–30 min · Make a half-length. Give each pair several large paper strips and ask students to fold and mark the halfway crease. Teacher circulates, checking that ends meet and that the fold is visible. Students label or point to the whole and each half, then compare one half with the other using “same length”. Revisit the folding demonstration and partner-task instructions if students need the steps repeated.

4. 30–45 min · Compare and sequence. Provide each pair with whole strips and folded half-length strips. Students place one end of each strip at the same starting point, compare them directly and arrange three objects from shortest to longest. After checking, they extend the sequence to five objects where ready. Students complete the measuring and sequencing worksheet by drawing or matching the ordered strips and orally explaining one comparison to a partner. Encourage complete sentences such as, “The half-strip is shorter than the whole strip.”

5. 45–54 min · Predict, test and discuss. Teacher shows a mixed collection of whole and half-length strips, including strips made from different starting lengths, and asks pairs to predict the order before measuring. Students use identical starting points to test their predictions, then use arrows to show shortest to longest. Discuss why a half of a long strip might be longer than a half of a short strip, and why the word half alone does not always tell us the exact length.

6. 54–60 min · Plenary and assessment. Display the final discussion prompt in the prediction, explanation and plenary slides. Students share one comparison using the sentence frame, “I know ___ is longer/shorter because…”. Finish with an oral exit check: each student points to a whole, a half and the shortest strip in a small displayed set, then explains one choice.

Resources

• the introduction and measuring sequence deck
• the measuring and sequencing worksheet
• Large paper strips in several lengths
• Crayons or pencils for marking fold lines
• Classroom table or floor space for sequencing
• Word and picture cards for whole, half, longer, shorter and same length
• Arrows or small labels marked shortest to longest

Assessment

• Observe folding: students should bring the two ends together and create two equal parts, rather than guessing the midpoint.
• During sequencing, check that students align strips at the same starting point and justify comparisons with accurate language.
• Use the final oral exit check to identify students who can recognise a half and compare length independently.

Differentiation

• Support learners with visible folding marks, large strips, identical starting points and paired measuring. Model each step slowly and use picture-supported vocabulary, gestures and oral rehearsal before writing.
• Begin with a three-item sequence. Provide arrows labelled shortest and longest, and allow students to place strips on the floor or table before recording on the worksheet.
• For dyslexia-friendly access, use large print, clear sans-serif text, minimal written instructions, strong visual contrast and repeated oral sentence frames. Accept pointing, drawing and spoken explanations.
• Extend confident learners by asking them to predict and test the order of mixed whole and half-length strips, including strips made from different starting lengths or measured using different informal units. Ask, “Can a half-strip be longer than another whole strip? How do you know?”