Identify Odd and Even Numbers - 2nd Grade Math

1. What is the ones-digit rule for an even number?

   It ends in $0,2,4,6,$ or $8$. Even numbers always have these digits in the ones place.

2. What does it mean if a group has an odd number of objects?

   After pairing, $1$ object is left over. Odd numbers always have one unpaired object.

3. Find and correct the mistake: A student says $8=3+5$ shows two equal addends.

   Correct: $8=4+4$. $3$ and $5$ are not equal; equal addends would be $4+4$.

4. What equation shows $4$ as a sum of two equal addends?

   $4=2+2$. Half of $4$ is $2$, so $4=2+2$.

5. What equation shows $10$ as a sum of two equal addends?

   $10 = 5 + 5$. Split $10$ into two equal parts.

6. If you count by $2$s and stop at $16$, how many pairs of $2$ did you count?

   $8$ pairs. Counting by $2$s: $2,4,6,8,10,12,14,16$ gives $8$ pairs.

7. Which numbers from $1$ to $20$ are odd?

   $1,3,5,7,9,11,13,15,17,19$. These numbers all have remainder $1$ when divided by $2$.

8. If $16$ objects are paired into groups of $2$, how many pairs are made?

   $8$ pairs. $16 ÷ 2 = 8$ pairs with none left over.

9. Identify whether $18$ is odd or even.

   $18$ is even. It ends in $8$, which makes it even.

10. What is the missing number: $14,16,\_,20$ when counting by $2$s?

    $18$. When counting by $2$s: $16+2=18$.

11. What equation shows $16$ as a sum of two equal addends?

    $16=8+8$. Half of $16$ is $8$, so $16=8+8$.

12. Identify whether $12$ is odd or even.

    $12$ is even. Ends in $2$, which makes it even.

13. Identify whether $20$ is odd or even.

    $20$ is even. Ends in $0$, which makes it even.

14. What equation shows $10$ as a sum of two equal addends?

    $10=5+5$. Half of $10$ is $5$, so $10=5+5$.

15. What does it mean if a number is even?

    Even means it can be split into $2$ equal groups with no leftovers. Even numbers divide evenly by $2$ with no remainder.

16. Choose the equation that shows an even number as two equal addends: $9=4+5$ or $14=7+7$?

    $14=7+7$. $14=7+7$ shows two equal addends; $9=4+5$ does not.

17. Identify whether $1$ is odd or even.

    $1$ is odd. It ends in $1$, which makes it odd.

18. What is the next even number after $12$?

    $14$. Even numbers increase by $2$: $12+2=14$.

19. Find and correct the equation to show $12$ as two equal addends: $12 = 5 + 7$.

    $12 = 6 + 6$. Split $12$ equally into $6 + 6$.

20. What does it mean if a group has an even number of objects?

    All objects can be paired with none left over. Even numbers divide into pairs perfectly.

21. Which numbers from $1$ to $20$ are even?

    $2,4,6,8,10,12,14,16,18,20$. These are all multiples of $2$ up to $20$.

22. Which option shows counting by $2$s to reach $10$: $1,3,5,7,9,10$ or $2,4,6,8,10$?

    $2,4,6,8,10$. Skip-counting by $2$s gives all even numbers.

23. What equation shows $14$ as a sum of two equal addends?

    $14 = 7 + 7$. Split $14$ into two equal parts.

24. Identify whether the equation $9 = 4 + 4$ is correct or incorrect.

    Incorrect. $4 + 4 = 8$, not $9$.

25. What does it mean if a number is odd?

    Odd means $1$ object is left over after making pairs of $2$. Odd numbers always have a remainder of $1$ when divided by $2$.

26. Which option describes an even number: "pairs with $0$ left" or "pairs with $1$ left"?

    "Pairs with $0$ left." Even numbers pair completely with no remainder.

27. What is the ones digit of an odd number (up to $20$)?

    $1$, $3$, $5$, $7$, or $9$. Odd numbers always end in these digits.

28. If $11$ objects are paired into groups of $2$, how many objects are left over?

    $1$ object left over. $11 ÷ 2 = 5$ pairs with $1$ remaining.

29. Which option describes an odd number: "pairs with $0$ left" or "pairs with $1$ left"?

    "Pairs with $1$ left." Odd numbers leave one object unpaired.

30. Write an equation showing $14$ as a sum of two equal addends.

    $14=7+7$. Half of $14$ is $7$, so $14=7+7$.

31. What does it mean for a number to be even?

    It can be split into $2$ equal groups with no leftovers. Even numbers divide evenly by $2$ with no remainder.

32. If $11$ objects are paired into $2$s, how many objects are left over?

    $1$. $11÷2=5$ remainder $1$, so $1$ object is left over.

33. Write an equation showing $8$ as a sum of two equal addends.

    $8=4+4$. Half of $8$ is $4$, so $8=4+4$.

34. What is the ones digit of an even number (up to $20$)?

    $0$, $2$, $4$, $6$, or $8$. Even numbers always end in these digits.

35. Identify whether $20$ is odd or even.

    $20$ is even. It ends in $0$, which makes it even.

36. Find the missing addend: $18=\square+\square$ with equal addends.

    $9$. Since $18÷2=9$, each addend must be $9$.

37. Identify whether $19$ is odd or even.

    $19$ is odd. Ends in $9$, which makes it odd.

38. If you pair $15$ objects into groups of $2$, how many objects are left unpaired?

    $1$ object is left unpaired. $15÷2=7$ remainder $1$, so $1$ object remains unpaired.

39. What is the next odd number after $15$?

    $17$. Odd numbers also increase by $2$: $15+2=17$.

40. Choose the correct equation for an even number: $9=4+4$ or $8=4+4$.

    $8=4+4$. $9$ is odd and cannot equal two equal addends.

41. What is the missing number: $2,4,6,\_,10$?

    $8$. When counting by $2$s: $6+2=8$.

42. Which method shows a number is even: pairing into $2$s or having $1$ left over?

    Pairing into $2$s with $0$ left over shows the number is even. Even numbers pair completely; odd numbers have one leftover.

43. What is the ones-digit rule for an odd number?

    It ends in $1,3,5,7,$ or $9$. Odd numbers always have these digits in the ones place.

44. What equation form shows an even number as a sum of two equal addends?

    $n=a+a$ (two equal addends). Even numbers can be written as double a single value.

45. Write an equation showing $20$ as a sum of two equal addends.

    $20=10+10$. Half of $20$ is $10$, so $20=10+10$.

46. What is the next even number after $14$?

    $16$. Add $2$ to get the next even number.

47. Which option shows counting by $2$s up to $12$ correctly?

    $2,4,6,8,10,12$. Starting at $2$, add $2$ each time to count by $2$s.

48. Identify whether $13$ is odd or even.

    $13$ is odd. It ends in $3$, which makes it odd.

49. What equation shows $12$ as a sum of two equal addends?

    $12=6+6$. Half of $12$ is $6$, so $12=6+6$.

50. Identify whether $0$ is odd or even.

    $0$ is even. Zero objects can be paired with none left over.

51. What does it mean for a number to be odd?

    It cannot be split into $2$ equal groups; $1$ is left over. Odd numbers have a remainder of $1$ when divided by $2$.

52. What equation shows $8$ as a sum of two equal addends?

    $8 = 4 + 4$. Split $8$ into two equal parts.

53. Find the missing addend: $12=\square+\square$ with equal addends.

    $6$. Since $12÷2=6$, each addend must be $6$.

54. Identify whether $7$ is odd or even.

    $7$ is odd. Ends in $7$, which makes it odd.

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