MathGrade 9ages 14–15
📊 Median
The median is the number sitting in the middle once a list is sorted from smallest to largest — skip the sorting, and "the middle number" means nothing at all.
Try this lesson freeNo card needed. The first lesson is free.
Download on the App StoreWhat your child learns
- First sort the numbers from smallest to biggest.
- The median is the one in the middle of the sorted row.
- With an even count, take the average of the two in the middle.
- An extreme value moves the average hard but barely moves the median, because it only takes up a place at the end.
The mistake most kids make here
Taking the middle of the list without sorting it first.
Try one question
What is the median of 3, 9 and 4?
3, 9, 4
- 4
- 9
- five and a third
Answer
4 — That's it. We sorted before we chose.
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: Say the median of the numbers 3, 9 and 4.
How to help at home
The word "middle" is doing double duty here: middle of the list as it was given, or middle of the list once it's in order. Only the second one is the median, and the difference matters every single time the list isn't already sorted.
Write three random numbers on paper, out of order, like 9, 3, 4. Ask your child for the median. If they say 3 (the middle one as written), have them sort the list first — 3, 4, 9 — and ask again. The median is 4.
When your child skips the sorting step, don't just give the right answer — ask "is this list already from smallest to biggest?" Make sorting a checkbox they tick before ever picking a middle number.
A sign they've got it: handed any short list of numbers in any order, they sort it first, automatically, before even talking about which one is the median.
Questions parents ask
- Why do I have to sort the numbers before finding the median?
- "Middle" only makes sense in an ordered list. A list of 3, 9, 4 has no real middle as written — sorting to 3, 4, 9 makes 4 the true middle value.
- What do I do if there's an even number of values?
- Sort the list, then average the two numbers sitting in the middle. For 2, 4, 6, 8, the two middle numbers are 4 and 6, so the median is 5.
- Why is the median sometimes better than the average?
- One extreme value can pull an average way off, but it barely moves the median, since an extreme value just takes up a spot at one end of the sorted list rather than dragging the middle.
- How does Maya teach the median?
- Maya has the child sort the numbers first, every time, before identifying a middle value, so 'median' never gets confused with 'the number in the middle of how it was written.'
No card needed. The first lesson is free.
Download on the App StoreMore Math lessons
- Not three rightsGrade 9
- 3-4-5Grade 9
- A parabolaGrade 9
- tanGrade 9
- Inscribed angleGrade 9
- What happens when the input growsGrade 8
- Rising or fallingGrade 8
- A system of equationsGrade 8