ExplorerGrades 1–2⏱ 10 min
Even and odd numbers
Pair up blocks two by two: even numbers match up perfectly, odd numbers leave one behind.
Standards: 2.OA.C.3
1Wonder
7 children want to play a game in pairs. Will everyone get a partner? What about 8 children? How can you tell without trying?
2Explore
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What to do
Purple blocks
Try this
- Make 7 blocks and press Pair them up. Is anyone left without a partner?
- Try 8, then 9, then 10. Which numbers always have one left over?
- Choose Add two numbers. Add two odd numbers, like 3 + 5. What happens to the two leftovers?
- What do you get when you add an odd number and an even number?
3Explain
Step 1 of 5
Even: everyone has a partner
6 blocks make 3 pairs with none left over. A number that splits into pairs with nothing left over is even.
Even and odd
Even numbers make pairs with none left over: 0, 2, 4, 6, 8, … Odd numbers have one left over: 1, 3, 5, 7, 9, …
even + even = even · odd + odd = even · odd + even = odd
4Practice
Question 1 of 5
Is 14 even or odd?
5Recap
- Even numbers make pairs with none left over; odd numbers have one left over.
- Even numbers end in 0, 2, 4, 6, 8; odd numbers end in 1, 3, 5, 7, 9.
- odd + odd = even (the two leftovers pair up); odd + even = odd.