MathGrade 6ages 11–12
❓ The hidden number
A letter like x can feel like a strange symbol rather than what it is: a place holding one particular number, waiting to be found.
Try this lesson freeNo card needed. The first lesson is free.
Download on the App StoreWhat your child learns
- A letter holds a place for one number.
- You find it by asking what is missing, because the equation already tells you everything except that.
- Check an answer by putting it back. If both sides come out equal, that is the number.
- The same letter in the same question is the same number.
The mistake most kids make here
Thinking the letter is an object rather than a number.
Try one question
x plus 4 equals 9. What is x?
x plus 4 equals 9
- 4
- 5
- 13
Answer
5 — That's it. Five plus four is nine, so it fits.
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 what x is when x plus 4 is 9.
How to help at home
The jump from arithmetic to algebra is really the jump from "calculate this" to "find what's missing". Children who are fine with 5 + 4 can freeze at x + 4 = 9 simply because a letter appeared.
Hide a small number of coins under a cup and put four more coins beside it. Say: "under the cup plus these four is nine coins total. How many are under the cup?" Let them lift the cup to check. The cup is x.
When your child treats the letter as an object rather than a number — asking "but what is x actually?" as if it's a thing, not a value — say: "x isn't a thing, it's a number we don't know yet. Our job is to find it, same as guessing what's under the cup."
A sign they've got it: given x + 4 = 9, they check their answer by substituting it back in, out loud — "5 plus 4 is 9, so that fits" — rather than announcing a number and moving on.
Questions parents ask
- Why does my child get confused by a letter standing for a number?
- Letters look like labels, not quantities, so it feels different from ordinary arithmetic. Concrete stand-ins — a covered cup, a closed box — bridge the gap because the child can physically check the answer.
- How do I explain finding x in a simple equation?
- Frame it as "what's missing": the equation already tells you everything except the hidden number, so the question is what value makes both sides come out equal.
- Why does the same letter always mean the same number in one problem?
- Because it's standing for one specific hidden value in that equation — not a symbol that can shift meaning mid-problem. Checking by substitution shows whether the same number really works everywhere it appears.
- How does Maya teach intro algebra?
- Maya starts from "what's missing" puzzles the child can check physically, like a hidden coin count, before introducing the letter as shorthand for that same idea.
No card needed. The first lesson is free.
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