Teaching fractions with play dough and plastic knives
Fractions can feel abstract when they are presented as shaded diagrams or numbers on a worksheet. Play dough gives students something they can hold, divide, reshape and discuss. With a plastic knife, a whole becomes a set of equal parts in front of them, making ideas such as halves, quarters and eighths easier to see.
This activity suits early primary learners, intervention groups and homeschool settings. It supports the language of Australian classrooms, where students may work towards the Australian Curriculum achievement standards while using familiar terms such as whole, equal parts, numerator and denominator. The tactile approach also gives children a practical way to show their thinking.
A small maths station can work in a Brisbane classroom, a homeschool room near Wagga Wagga or a composite class in regional Western Australia. The materials are inexpensive, reusable and easy to pack away before lunch or the afternoon “arvo” session. Roylco’s classroom ideas can provide further inspiration for hands-on learning activities across the curriculum.
Make the whole visible
Begin with one ball of play dough for each student or pair. Ask learners to describe it as one whole before they flatten it into a thick circle, rectangle or “pizza”. The shape does not need to be perfect; the key idea is that the entire piece represents one.
Use a plastic knife to cut the whole into two parts. Students should place the pieces together again and check whether they are equal. Introduce the sentence, “Two equal parts make one whole,” then repeat the process with four and eight parts. This physical checking helps children understand that a fraction describes a relationship between the parts and the original whole.
Encourage students to use precise language: half, halves, quarter, quarters, eighths, equal, unequal and whole. If one slice is larger, call it an unequal part rather than accepting it as a quarter. This distinction is important because children often focus on the number of pieces without considering their size.
Set up a safe maths station
Choose soft, non-toxic modelling dough and blunt plastic knives designed for children. Demonstrate how to cut away from the body, keep the tool on the work surface and pass it handle-first. Young children should be supervised, and materials should be checked for damage before and after the lesson. Play dough is for modelling rather than eating, so establish that rule clearly.
Give each group a work mat, a dough portion and a small set of fraction cards. A card might show “make three quarters”, “show one half in two different ways” or “find a fraction equal to two quarters”. Students can cut, rearrange and explain their answer to a partner. For students with fine-motor difficulties, a thicker dough piece, a non-slip mat or a larger-handled tool can make the activity more accessible.
In Australian schools, shared resources may need to serve several year levels and classrooms. Store each set in a labelled tub, and use coloured dough to help groups identify their materials. A simple photo of a completed model can support students who need a visual reminder of what to do next.
Build equivalent fractions through cutting
Once learners can make equal parts, show how the same amount can have different names. A circle divided into two equal pieces can be cut across again to create four equal pieces. Two of those four pieces cover the same amount as one half. Students can test this by placing the play dough pieces on top of one another.
| Dough model | Fraction name | Equivalent statement |
|---|---|---|
| One of two equal parts | 1/2 | 1/2 = 2/4 |
| Two of four equal parts | 2/4 | 2/4 = 4/8 |
| Three of four equal parts | 3/4 | 3/4 = 6/8 |
| One of four equal parts | 1/4 | 1/4 = 2/8 |
Ask students to record each model with a drawing and a number sentence. They can then compare 1/2, 2/4 and 4/8 and explain why the values are equal. For a challenge, provide two dough circles of the same size and ask learners to show why one quarter is smaller than one half even though both fractions have a one on top.
The plastic knife makes the denominator meaningful: it tells how many equal parts the whole has been divided into. The numerator identifies how many of those parts are selected. Students can point to each part while saying the fraction aloud, connecting the spoken, visual and symbolic forms.
Compare, order and solve
Use play dough strips to compare fractions with the same denominator. Students can make one strip, divide it into six equal parts and shade or remove different numbers of pieces. They will see that five sixths is greater than two sixths because five parts occupy more of the same-sized whole.
For fractions with different denominators, use matching wholes. Make one circle in halves and another circle in quarters, keeping both circles the same size. Lay the pieces side by side to compare one half and two quarters. This avoids a common misconception: assuming that a larger denominator always means a larger fraction.
The models also support simple addition and subtraction. To show one quarter plus two quarters, students place three quarter pieces together and name the result as three quarters. For subtraction, they can remove one eighth from five eighths. Keep the examples within the learners’ current level and require an explanation alongside the answer.
A movement-based variation works well in a busy Australian classroom. Place fraction cards around the room and ask pairs to carry their dough model to the matching card. In a smaller homeschool setting, children can use household objects as comparison prompts, such as dividing a pretend lamington tray or sharing an imaginary watermelon fairly.
Connect fractions to broader learning
Fraction work can lead naturally into measurement, patterns, food technology and social learning. Students can make a “fraction bakery”, label dough biscuits as halves or quarters, and discuss fair sharing. They can also explore repeated patterns by arranging eighths in alternating colours. These extensions keep the maths anchored in a meaningful situation rather than separating it from everyday life.
A class map activity can connect equal parts with location and scale. After students divide a play dough strip into equal sections, they might label each section as a classroom zone or map grid. Roylco’s floor map activity offers a useful bridge between practical modelling, spatial language and social studies.
Assess learning by listening to explanations and looking for three features: equal-sized parts, accurate fraction language and a clear connection between the model and the written fraction. A child who can build three quarters but calls it “three out of three” needs language support, while a child who explains that four eighths is the same amount as one half is showing developing equivalence.
The final models can be photographed for portfolios, displayed beside student explanations or used as prompts in a later lesson. Through cutting, checking and rebuilding, fractions become something students can handle, describe and reason about rather than symbols they must memorise.