MathGrade 4ages 9–10
🥄 Grams and kilos
A child who has not yet separated "a number" from "a number of what" may add 250 and 3 straight across, because grams and kilos both just look like numbers on the page.
Try this lesson freeNo card needed. The first lesson is free.
Download on the App StoreWhat your child learns
- In one kilogram there are a thousand grams.
- Grams and kilos are two names for the same kind of weight, at different sizes.
- You cannot add numbers from two different units as if they were the same.
- Convert to the same unit first, and only then add.
The mistake most kids make here
Adding kilos to grams without converting first.
Try one question
Four portions of 250 grams. How many kilos together?
250 × 4
- 1
- 250
- 1000
Answer
1 — Yes. A thousand grams is exactly one kilo.
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: How many grams are in a kilo, and why can you not add without converting?
How to help at home
This is not a sign of weak arithmetic — it is a sign that the two units have not yet been lined up as the same kind of thing at different sizes. A kitchen scale makes that concrete.
Weigh a bag of flour that is exactly one kilo, then weigh four 250-gram butter blocks next to it. Let your child see the scale read the same number both ways: a kilo is a thousand grams, no more and no less.
When they add units without converting, ask: "are these two numbers the same kind of thing?" Before adding 250 grams and 3 kilos, both need to be grams, or both need to be kilos — pick one and rewrite the other.
A sign they have it: given 500 grams and 2 kilos, they convert one side on their own before adding, without being reminded which unit to use.
Questions parents ask
- Why does my child add grams and kilos as if they were the same number?
- At this stage a number on the page can look complete on its own, so the unit attached to it gets overlooked. Converting both amounts to one unit before adding, out loud, makes the missing step visible.
- What is a good way to practice grams and kilograms at home?
- Use a kitchen scale on real food. Weigh several small items in grams, then group them until they reach a kilo, so the number 1000 stops being abstract.
- Is there a quick way to convert between grams and kilos?
- A kilogram is always 1000 grams, so grams to kilos means dividing by 1000, and kilos to grams means multiplying by 1000 — moving the point three places.
- How does Maya teach grams and kilograms?
- Maya has the child convert both amounts to the same unit before adding, so the rule is rebuilt from the mismatch itself rather than handed as a fact to memorize.
No card needed. The first lesson is free.
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