1st Grade Math Practice · Addition & Subtraction Within 20 · Challenge Level

1st Grade Math Practice: 20 Harder Multiple-Choice Questions on Addition & Subtraction Within 20

A challenge-level practice set for 1st grade students who are ready to push past the basics. Twenty multiple-choice questions on addition and subtraction within 20 — with two-step problems, missing addends in trickier positions, comparison traps, true/false reasoning, and short word problems. Four options per question, full explanation for every answer. Built by the SOMATH team on the Upper West Side.

· By the SOMATH team · 226 W 79th St, UWS · (646) 668-6151

Who this is for. A 1st grader who already knows the addition and subtraction facts to 10 and is comfortable crossing 10 with single-digit problems. These questions step it up: two-step word problems, missing addends in any of the three positions, true/false reasoning, and comparison problems with a built-in trap. If your child is still warming up, start with our easier K–1 practice set first.

What's inside

  1. How to use this practice set
  2. 20 multiple-choice questions — mid difficulty, four options each
  3. How to coach a 1st grader through these
  4. Want a teacher to walk through them with your child?

How to use this practice set

Sit with your child. Read each question out loud, then read the four choices A, B, C, D. Let the child point to or say their answer before tapping Show answer. The explanation under each answer is written so a parent can read it aloud — we never just give the number, we always show why.

All 20 questions stay inside the range 0–20, the official ceiling for the Common Core 1st grade operations and algebraic thinking standards (1.OA). These lean toward the top end of 1st grade: two-step problems (1.OA.A.2), missing addends in any position (1.OA.D.8), comparison problems with a trap (1.OA.A.1), and true/false reasoning (1.OA.D.7). None require carrying with two-digit numbers — that's a 2nd grade skill.

20 multiple-choice questions

Level: Challenge · 1st grade

Question 1 of 20

Two-step word problem. Maya has 7 stickers. Her brother gives her 5 more. Then she uses 4 stickers on a card. How many stickers does Maya have now?

  1. 6
  2. 7
  3. 8
  4. 9

Answer: C — 8

This is a two-step problem — you have to do two operations in order. Step 1: 7 + 5 = 12 (her brother gives her more). Step 2: 12 − 4 = 8 (she uses some). Two-step problems are the biggest leap in 1st grade because the child must hold the result of step 1 in their head while they do step 2.

Question 2 of 20

Fill in the missing number: ? + 6 = 14

  1. 6
  2. 7
  3. 8
  4. 9

Answer: C — 8

The unknown is in the first position, which is the hardest of the three positions for 1st graders. Think of it as 14 − 6 = 8. Check: 8 + 6 = 14. ✓ Or count up from 6 to 14 on your fingers: 7, 8, 9, 10, 11, 12, 13, 14 — that's 8 jumps.

Question 3 of 20

Word problem. Liam has 14 marbles. Noah has 6 marbles. How many more marbles does Liam have than Noah?

  1. 6
  2. 8
  3. 14
  4. 20

Answer: B — 8

"How many more" is a comparison question, which uses subtraction: 14 − 6 = 8. Liam has 8 more marbles than Noah. The trap is choice D (20) — that's the total number of marbles. The trap is choice C (14) — that's Liam's count. The trap is choice A (6) — that's Noah's count. Only the difference, 8, answers the question.

Question 4 of 20

Which number sentence below is FALSE?

  1. 9 + 7 = 16
  2. 13 − 5 = 7
  3. 8 + 6 = 14
  4. 11 − 4 = 7

Answer: B — 13 − 5 = 7

Check each: 9 + 7 = 16 (true). 13 − 5 = 8, NOT 7 (false). 8 + 6 = 14 (true). 11 − 4 = 7 (true). The misleading one is the trick: if your child uses 13 − 5 to check, the matching addition is 5 + 8 = 13, so the right answer is 8, not 7.

Question 5 of 20

Two-step word problem. There are 15 birds on a fence. 8 fly away. Then 5 more land on the fence. How many birds are on the fence now?

  1. 10
  2. 11
  3. 12
  4. 13

Answer: C — 12

Two steps, opposite operations. Step 1: 15 − 8 = 7 birds left after the first group flies away. Step 2: 7 + 5 = 12 birds after new ones arrive. Doing them in the wrong order (e.g., 15 − 8 + 5 read as 15 − 13) gives a wrong answer — order matters in word problems.

Question 6 of 20

Find the missing number: 17 = 9 + ?

  1. 6
  2. 7
  3. 8
  4. 9

Answer: C — 8

Many 1st graders pause at this because the sum is written before the equals sign. But "=" means same value on both sides, not "the answer comes next." So 9 + ? = 17, which means ? = 17 − 9 = 8. This is the start of real algebraic thinking (Common Core 1.OA.D.7).

Question 7 of 20

What is 4 + 7 + 6?

  1. 15
  2. 16
  3. 17
  4. 18

Answer: C — 17

Adding three numbers (1.OA.A.2). The smart move is to rearrange to find a pair that makes 10: 4 + 6 = 10, then 10 + 7 = 17. Doing it left to right also works (4 + 7 = 11, 11 + 6 = 17), but the make-a-ten strategy is faster and less error-prone. Addition can be done in any order — that's the commutative property.

Question 8 of 20

Which symbol goes in the box: 15 − 7  [ ? ]  6 + 3

  1. > (greater than)
  2. < (less than)
  3. = (equal to)
  4. None of the above

Answer: B — < (less than)

Solve both sides first: 15 − 7 = 8 and 6 + 3 = 9. Then compare: 8 < 9. The trap is that the left side looks bigger because of the 15 — but after the subtraction it's only 8. Memory hook: the wide opening of < or > always faces the bigger value.

Question 9 of 20

Fill in the missing number: ? − 7 = 8

  1. 14
  2. 15
  3. 16
  4. 17

Answer: B — 15

The unknown is the starting amount before subtraction. To undo a subtraction, add: ? = 8 + 7 = 15. Check: 15 − 7 = 8. ✓ Many 1st graders see "− 7" and reflexively want to subtract — but when the unknown is the start, you add to find it.

Question 10 of 20

Word problem. A puzzle has 20 pieces in total. Sofia has placed 13 pieces. How many more pieces does she still need to place?

  1. 6
  2. 7
  3. 8
  4. 9

Answer: B — 7

Two ways to set this up: (1) 20 − 13 = 7 pieces remaining. (2) 13 + ? = 20, so ? = 7. Both are correct and use exactly the same fact family. "How many more to reach" or "how many still need" is a classic missing-addend signal.

Question 11 of 20

Use the doubles fact 8 + 8 = 16 to solve 8 + 9.

  1. 15
  2. 16
  3. 17
  4. 18

Answer: C — 17

This is the near-doubles strategy. 8 + 9 is one more than 8 + 8, so 8 + 9 = 16 + 1 = 17. Once a 1st grader knows the doubles (4+4, 5+5, 6+6, 7+7, 8+8, 9+9), every "near-double" (e.g., 6+7, 7+8, 8+9) becomes one addition fact + 1.

Question 12 of 20

Which equation is part of the same fact family as 6 + 8 = 14?

  1. 14 + 6 = 20
  2. 14 − 6 = 8
  3. 8 + 6 = 12
  4. 6 − 8 = 14

Answer: B — 14 − 6 = 8

A fact family is a group of four equations using the same three numbers. For 6, 8, 14 the family is: 6 + 8 = 14, 8 + 6 = 14, 14 − 6 = 8, 14 − 8 = 6. Only choice B is one of those four. Choice A changes the numbers; choice C uses 12 instead of 14; choice D is mathematically impossible.

Question 13 of 20

What is 16 − 9?

  1. 6
  2. 7
  3. 8
  4. 9

Answer: B — 7

Crossing back across 10 is tricky. Two clean strategies: (1) Back to 10 first: 16 − 6 = 10, then 10 − 3 = 7. (2) Use the addition partner: 9 + 7 = 16, so 16 − 9 = 7. The second is faster once doubles and near-doubles are memorized.

Question 14 of 20

Word problem. Eli has 16 books. He has 7 more books than Mia. How many books does Mia have?

  1. 7
  2. 8
  3. 9
  4. 10

Answer: C — 9

Eli has MORE, so to find Mia's count we have to subtract: 16 − 7 = 9. Many 1st graders see the word "more" and add — that gives the wrong answer of 23 (way over 20). The rule: the word "more" tells you who has the bigger pile, not always which operation to use.

Question 15 of 20

Fill in the missing number: 5 + 6 + ? = 18

  1. 5
  2. 6
  3. 7
  4. 8

Answer: C — 7

Two steps. Step 1: 5 + 6 = 11 (the known part). Step 2: 11 + ? = 18, so ? = 18 − 11 = 7. Check: 5 + 6 + 7 = 18. ✓ This combines three skills: adding three numbers, finding a missing addend, and subtracting across 10.

Question 16 of 20

Which equation is TRUE?

  1. 7 + 8 = 9 + 4
  2. 4 + 9 = 5 + 8
  3. 6 + 7 = 8 + 4
  4. 9 + 5 = 7 + 6

Answer: B — 4 + 9 = 5 + 8

Compute each side: A: 7+8=15, 9+4=13 ✕. B: 4+9=13, 5+8=13 ✓. C: 6+7=13, 8+4=12 ✕. D: 9+5=14, 7+6=13 ✕. Only B is true. The slick way to see it without computing: take 1 from the 9 and give it to the 4 → you get 5 + 8 on the other side. That's the balance trick, an idea your child will see again in algebra.

Question 17 of 20

Word problem. Some children were in the park. 6 more children came to play. Now there are 14 children. How many children were in the park to start?

  1. 7
  2. 8
  3. 9
  4. 10

Answer: B — 8

The start is unknown — the hardest type of word problem in 1st grade. Set it up: ? + 6 = 14. Solve: ? = 14 − 6 = 8. Eight children were there before the new group arrived. The clue: "6 more came" tells you that 6 was added to the starting amount.

Question 18 of 20

What is 18 − 9?

  1. 7
  2. 8
  3. 9
  4. 10

Answer: C — 9

This is a doubles partner. Since 9 + 9 = 18 (the double), 18 − 9 = 9. Anytime the answer matches one of the addends, you're looking at a doubles family. Memorizing doubles automatically gives you all the matching subtractions: 18 − 9, 16 − 8, 14 − 7, 12 − 6, 10 − 5.

Question 19 of 20

Which expression is NOT equal to 13?

  1. 6 + 7
  2. 20 − 7
  3. 9 + 5
  4. 15 − 2

Answer: C — 9 + 5

Compute each: 6 + 7 = 13 ✓. 20 − 7 = 13 ✓. 9 + 5 = 14 — not 13. 15 − 2 = 13 ✓. Only C is the odd one out. The skill being tested is "flexible representation" — understanding that the same number (13) can be written in many ways, and being able to spot the impostor.

Question 20 of 20

Challenge. Ben had some pencils. He bought 8 more, then gave 5 to his cousin. Now Ben has 11 pencils. How many pencils did Ben have at the start?

  1. 6
  2. 7
  3. 8
  4. 9

Answer: C — 8

Work backwards. He ends with 11. Before giving 5 away he had 11 + 5 = 16. Before buying 8 more he had 16 − 8 = 8. So Ben started with 8 pencils. Check forwards: 8 + 8 − 5 = 11. ✓ Solving backwards is a powerful problem-solving trick — the same idea your child will use in algebra to "undo" equations.

How to coach a 1st grader through these

Three habits from our Upper West Side classroom:

  1. Always ask "how did you decide?" Even when the answer is right. A 1st grader who can explain "I broke the 5 into 2 and 3 so I could make a ten" is building real fluency. A 1st grader who only says "I just knew it" is still guessing.
  2. Use the addition family for every subtraction. 13 − 5 is hard. But "5 + ? = 13" feels easier to most kids. Remind them: every subtraction problem has a partner addition fact. Find the partner, then answer.
  3. Catch the wrong-operation trap in word problems. When a problem says "how many more," young students often add instead of subtract. Have your child circle the key phrase and say out loud whether it means + or − before doing any math.

If your child gets stuck on a question:

  • "Can you draw it — with circles, sticks, or a number line?"
  • "Is there a way to make a ten first?"
  • "What's the matching addition (or subtraction) fact for this one?"

If those three don't unlock it, the issue is a missing prerequisite — usually the addition facts to 10, or the meaning of an operation word. That's exactly what we diagnose in our free 60-minute evaluation.

Want a teacher to walk through these with your child?

Our Little Newtons short course is built for K–2 students, taught in person at 226 W 79th St, 1st Floor, Upper West Side. Small groups, real notebooks, no worksheet stacks.

Free 60-minute evaluation with a written diagnostic within 48 hours, even if you don't enroll.

Call (646) 668-6151 or book your evaluation online.

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SOMATH course · Grades 1–2

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