Concept 4 of 5
Number Pairs: Copy the Rule
Today's big idea
Find the rule, run it again
Double, minus 2, plus 10 — reuse it.
How it works
👀 What's going on?
Give a machine a 2 and it hands back a 4; give it a 3 and it hands back a 6. Once you see it always doubles, you can feed it any number. Number analogies are little machines like that.
💡 Here's the trick
A number analogy reads A : B :: C : ?. Find the rule that turns A into B — double it, take 2 away, add 10 — then run the third number through the same rule.
- 1.Look at the first pair and find the rule (×2, −2, +10).
- 2.Check the rule works for that pair.
- 3.Use the same rule on the third number.
✍️ Try it
- 1.2 : 4 :: 3 : ?
- 2.9 : 7 :: 5 : ? Pair 1 doubles, so 3 becomes 6. Pair 2 takes 2 away, so 5 becomes 3.
⚠️ Watch out
One pair can look like more than one rule. 2 : 4 could be +2 or ×2. Check the answer choices and the numbers again — the rule that fits both parts is the right one.
See it in action
⚡ Time to play!
Find the rule that turns the first number into the second, then use it on the third.
NUMBER ANALOGY · ROUND 1 OF 3
Which number completes the pair?
Quick check
✅ VERIFICATION
2 is to 4 as 5 is to ___? (each number doubles)
⚡ Finish the activity above first to answer.
Keep going!
Up next: Letter Pairs
One letter on, two on, or one back — copy the hop.