Adding Like Fractions

Overview

This is lesson 5 of 10 in Understanding Fractions Together. Students model and add fractions with the same denominator using visual representations, then record the addition sentence. The lesson is designed for older students working broadly within Years 2–4 achievement levels, with explicit modelling and repeated opportunities to explain thinking.

Learning intentions

• WALT add fractions with the same denominator.
• Students will recognise that the denominator stays the same when equal-sized parts are combined.
• Students will use fraction strips, drawings and number sentences to solve addition problems.
• Students will identify when a result makes one whole and write it as 1 where appropriate.

Success criteria

• I can identify the denominator in two fractions.
• I can add the numerators and keep the denominator the same.
• I can show my answer with a model, drawing or number sentence.
• I can recognise and record one whole when all equal parts are combined.

Curriculum links

• Recognising and representing common fractions as equal parts of a whole.
• Comparing and explaining the relationship between the numerator and denominator.
• Solving simple addition problems involving fractions with the same denominator.
• Using materials, drawings, symbols and mathematical language to communicate reasoning.

Lesson structure (45 minutes)

1. 0–5 minutes – Connect to prior learning Display the opening question in the fraction addition introduction deck: “If two equal pieces of a cake are put together, how many pieces do we have?” Use a familiar visual such as a pizza or chocolate bar divided into equal parts. Ask students to recall that the denominator tells us how many equal parts make the whole, while the numerator tells us how many parts we have.

2. 5–13 minutes – Explicit teaching and modelling Use the worked-example slides to model (1/4 + 2/4). Build one quarter and two quarters with the fraction strips from the fraction wall and strip cards, then combine them to make three quarters. Write:

• The parts are the same size, so the denominator stays 4.
• Add the numerators: 1 + 2 = 3.
• (1/4 + 2/4 = 3/4). Repeat with (2/5 + 2/5 = 4/5). Emphasise that students add the number of parts, not the denominators.

3. 13–20 minutes – Guided practice Give pairs selected fraction strips from the fraction wall and strip cards. Display one problem at a time in the guided-practice slides. Students build each fraction, push the strips together and explain the answer to their partner:

• (1/3 + 1/3)
• (2/6 + 1/6)
• (3/8 + 2/8)

Pause after each example to check: “What stayed the same?” and “What did we add?” Support students to say the complete sentence, for example, “Three sixths plus one sixth equals four sixths.”

4. 20–32 minutes – Scaffolded independent practice Distribute the scaffolded like-denominator fractions worksheet. Students complete the visual and symbolic questions independently or with a partner. The worksheet should progress from shaded models and sentence frames to equations, including:

• (1/4 + 1/4)
• (2/5 + 1/5)
• (3/8 + 2/8)
• (4/6 + 2/6)

Encourage students to use the fraction strips or draw equal parts before writing an answer. Confer with individuals and ask them to explain how they know the denominator remains unchanged.

5. 32–38 minutes – Whole-making discussion Use the whole-making discussion slides to show (2/4 + 2/4), (3/6 + 3/6) and (4/4). Students build or draw each example. Discuss that (4/4) is one whole and can be recorded as (1). Do not require formal reduction beyond recognising a complete whole; accept a correct visual and either (4/4) or (1), depending on student readiness.

6. 38–43 minutes – Explain and check Display the final challenge on the reasoning and exit prompt slide: “Sam says (1/5 + 2/5 = 3/10). Is Sam correct? Show why.” Students respond using a drawing, fraction strips or words. Invite two students to share different representations and correct the misconception that denominators are added.

7. 43–45 minutes – Plenary and review Ask each student to complete the oral sentence: “When fractions have the same denominator, I…” Collect the worksheet or photograph completed work. Revisit the WALT and success criteria, asking students to show a thumb signal for the part they can do confidently and identify one part needing more practice.

Resources

• the fraction addition introduction deck
• the scaffolded like-denominator fractions worksheet
• the fraction wall and strip cards
• Whiteboard and markers
• Pencils and erasers
• Optional mini-whiteboards
• Prepared examples using quarters, fifths, sixths and eighths

Assessment

• Observe whether students build equal-sized parts correctly and keep the denominator unchanged.
• Check worksheet answers, drawings and explanations for accurate addition of numerators.
• Use the final misconception question to identify students who add denominators or need further modelling.

Differentiation

• Support: provide a step-by-step visual guide on the worksheet: build the first fraction, build the second fraction, count the parts, keep the denominator, write the answer. Use denominators of 2, 3 and 4 first.
• Support: allow students to work with a teacher or trusted partner, use concrete fraction strips, trace numerals and respond orally before recording.
• EAL/D and communication support: use repeated sentence frames such as “___ parts plus ___ parts equals ___ parts” and display numerator, denominator and whole with clear visual labels.
• Extension: invite confident students to solve examples where the total is one whole, such as (3/6 + 3/6), and explain why the answer can be written as both (6/6) and (1).