Math · Stage 6
Use letters to represent numbers; simplify and evaluate simple expressions
Let a letter stand for a hidden number, collect like terms to simplify an expression, then swap the letter for a number to evaluate it — your first real algebra.
✦ Math📘 Stage 6 · S6⏱ ~14 min🧒 Ages 10–12★ Free to start
I can use letters to represent numbers; simplify and evaluate simple expressions.
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Kavi's Mystery Acorns 🌰
Kavi hides some acorns in a cup and calls the hidden number a. "A letter is just a number in disguise!" she hoots. "Two cups is a + a = 2a, and once I peek and see 4 acorns, then 2a = 8. A letter lets me write a rule before I even know the number ⚡."
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What your child will learn
1A letter stands for a numberWhen we do not know a number yet, we can write a letter for it. If a cup holds a acorns, then a cup and another cup is a + a, which is 2 lots of a — written 2a. Tap a row to read it.
2Like terms vs unlike termsYou can only add counts of the same letter. 3a + 2a are like terms — same letter, so they join into 5a. 3a + 2b are unlike terms — different letters, so they must stay apart. Tap each card.
3Simplify: collect the like termsTo simplify, gather the like terms and add or subtract their counts. The plain numbers (with no letter) gather together too. Tap a row to see it tidied up.
4Evaluate: swap the letter for a numberWhen someone tells you what the letter is, you evaluate the expression: put the number in place of the letter, then work it out. Here every letter a is worth 4. Tap a row.
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A peek inside
Simplify: 4a + 3a
same letter a — add the counts: 4 + 3 = 7 lots of a
Try this at home: Write it with a letter: a bag holds n marbles. Three more marbles is __
Ready to play and learn?
Start the free interactive lesson, or print the handout for screen-free play.
Part of Math · Stage 6 · S6 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.