MathGrade 5ages 10–11
🧱 Unlike denominators
A child who treats a fraction as two separate numbers stacked on top of each other may add both the top and bottom numbers, because nothing yet tells them the bottom number is the size of the piece, not a quantity to add.
Try this lesson freeNo card needed. The first lesson is free.
Download on the App StoreWhat your child learns
- Adding fractions is counting pieces, and you only count things of the same size.
- A half and a quarter are pieces of different sizes, so they cannot be counted together.
- Cut the half into two quarters, and now everything is the same size.
- Only then do you count: two quarters and one quarter is three quarters.
The mistake most kids make here
Adding the numerators and the denominators to each other.
Try one question
How much is a half plus a quarter?
1/2 + 1/4
- 3/4
- 2/6
- 1/6
Answer
3/4 — Yes. Three quarters.
How Maya teaches it
Your child tells Maya what they did in class. She teaches this topic at her desk, asks questions with tappable answers, and when the answer is wrong she explains why that answer was tempting instead of saying “try again”. She remembers what did not land and comes back to it.
Your child has it when they can: Why do you need a common denominator before adding?
How to help at home
Adding fractions is really just counting, and you can only count things that are the same size. Adding 1/2 + 1/4 as 2/6 skips the step of making the pieces match first.
Cut a real pita or pizza in half, then cut the other half into two quarters. Physically place a quarter-slice next to a half-slice and ask: are these the same size? They are not, so they cannot be counted together yet.
Cut the half slice into two quarters too. Now every piece on the table is a quarter, and your child can count them directly: two quarters plus one quarter is three quarters.
A sign they have it: before adding two fractions, they check on their own whether the denominators match, and know that a different denominator means the pieces are a different size.
Questions parents ask
- Why does my child add 1/2 + 1/4 and get 2/6?
- They are adding the top numbers and the bottom numbers separately, as if a fraction were two unrelated numbers, instead of recognizing the bottom number as the size of each piece.
- What is a hands-on way to practice adding unlike fractions?
- Use a real object you can cut — a pita, a chocolate bar, a piece of paper — and physically resize the pieces so they match before counting them.
- How do you find a common denominator?
- Find a number both denominators divide into evenly, then rewrite each fraction with that denominator by multiplying its top and bottom by the same amount.
- How does Maya teach adding fractions with unlike denominators?
- Maya has the child physically resize pieces to match before counting, so the need for a common denominator comes from seeing mismatched sizes rather than from a memorized rule.
No card needed. The first lesson is free.
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