A No-Prep Sub Plan for Fractions (New Zealand)

Fractions are the worst possible topic to leave to chance. A reliever with a general primary background can run a spelling lesson on instinct, but a well-meaning explanation of equivalent fractions from someone who half-remembers the rule can undo a fortnight of your teaching. So the fractions relief lesson has to be chosen for one property above all: it must not require anybody at the front to explain anything.

Pick a task that cannot be taught wrongly

Comparing and ordering fractions with visual support fits. Adding fractions with unlike denominators does not, because the moment a student asks why, the reliever either invents a rule or freezes. Anything procedural is a trap; anything checkable against a drawing is safe. For a Year 4 to Year 6 class working around curriculum level 3, the lesson below uses one idea, three rounds and a physical check that removes the need for adult expertise. It runs in fifty minutes and shortens to thirty-five cleanly.

The lesson: one idea, three rounds

Round one, ten minutes. Every student gets four paper strips of identical length. They fold one into halves, one into quarters, one into eighths, and leave one whole. Nothing is written yet. The reliever's only instruction is to fold carefully and label each piece. Folding is a task any adult can supervise, and it builds the reference model the rest of the lesson leans on.

Round two, twenty minutes. Pairs are given eight fraction cards and asked to order them smallest to largest using the strips to check. Every disagreement is settled by laying strips side by side, not by the adult. The learning purpose is comparing fractions by size rather than by numerator, which is where the classic error lives.

Round three, fifteen minutes. Each student writes three statements in their book, using the words bigger than, smaller than and the same as, and draws the strip evidence beside each one. This is the work you collect.

A folder of short printable fraction and number tasks means the reliever always has a next thing when a pair finishes in twelve minutes, and the Free Math Resource Pack – Number Sense for Grades 1–4 is a sensible thing to keep photocopied in the relief drawer because it needs no explanation before a student can start.

What the reliever should say, word for word

Write these on the plan in quotation marks and nothing else:

• "Fold it in half, then in half again. Now label every piece."
• "If you two disagree, put the strips next to each other. The strips are the boss, not me."
• "I am not going to tell you which is bigger. Show me with the paper."
• "Three sentences in your book, with a drawing beside each one."

The third line gives a non-specialist permission to refuse a question they cannot answer, which is the biggest source of misinformation in a relief maths lesson. Add a note telling them to leave any question about adding fractions to you.

The three places it usually goes wrong

Strips of unequal length break the model, so the plan must say to cut them from one sheet folded together. Students who write answers without drawings defeat the point, so name the drawing first and the sentence second. And an early-finishing pair with nothing to do becomes the incident reported to you at four o'clock, so the plan needs a named extension on the reliever's desk. Warm-up sheets do that job well, and having the Grade 4 Math Warm-Up Worksheets printed and clipped to the plan means the extension does not depend on anybody finding the photocopier code.

What the books tell you the next morning

Read for the drawings, not the sentences. A student who wrote "three quarters is bigger than two thirds" with a strip drawing that shows it has reasoned. The same sentence with no drawing may be a lucky guess from counting numerators. Those two students need different lessons, and one pass through the books tells you which is which.

Sort the class into the ones who used the model and the ones who avoided it, and start Monday with the avoiders in a group at the back table. Where the gap is really about number sense rather than fractions, dropping back to shorter daily practice for a fortnight is more effective than pressing on, and the Grade 3 Math Warm-Up Worksheets give you that repair work in five-minute doses. A relief day handled this way costs you a lesson of pace and gains you a class list you would otherwise have spent a week assembling.

Related reading from the Teacher Hub

• Using Digital Tools to Teach Linear Functions (New Zealand)
• A Project-Based Unit on Probability: Planning It Week by Week (New Zealand)
• Revision and Exam Preparation for Times Tables (New Zealand)