Math · Stage 6
Defining and evaluating new operations
A 'new operation' is just a made-up rule with its own sign. Read the rule, slot your two numbers in, and work it out — exactly the kind of puzzle maths olympiads love.
✦ Math📘 Stage 6 · S6⏱ ~12 min🧒 Ages 10–12★ Free to start
I can evaluate a defined new operation.
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Kavi Invents a Button 🔘
Kavi drew a brand-new sign on the board — a little star: ★. “It isn't plus, it isn't times,” said Kavi. “I made it up! Here is its rule: a ★ b = a + b + 1.” Dev tried one: 3 ★ 4 = 3 + 4 + 1 = 8. “See?” beamed Kavi. “A new operation is just a rule in disguise — read it, pop your numbers in, and evaluate!”
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What your child will learn
1Meet a brand-new operation★ is not a real maths sign — someone just invented it and gave it a rule. To use it, slot the two numbers into the rule in order and work it out. Tap a row to hear the answer.
2The order can change the answerHere is a different rule: a ◆ b = 2 × a + b. The first number gets doubled, so swapping the two numbers can change the answer. Tap each card.
3Evaluate, then sort by the answerUse the star rule a ★ b = a + b + 1. Work out each one, then drop it in the box that shows its answer.
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A peek inside
A new operation ★ is defined by a ★ b = a + b + 1. What is 6 ★ 2?
slot the numbers into the rule: 6 + 2 + 1
Try this at home: ★: a ★ b = a + b + 1. Find 4 ★ 5 → __
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.