1st Grade Subtraction Within 20 Test Solutions and Scoring (PDF)
This subtraction within 20 test answers for 1st Grade covers subtraction within 20 (Common Core 1.OA.A.1, 1.OA.B.4, 1.OA.C.6), with a free PDF to print.
This answer key shows each solution and how many points each part earns. Give full credit when the sentence and the answer are both correct. Give partial credit for a right method with a small counting slip.
Grade 1 · Common Core State Standards: 1.OA.A.1, 1.OA.B.4, 1.OA.C.6
Subtraction within 20 test answers: worked solutions
Question 1 – Crossed-out counters [2 pts]
- \(11 – 4 = 7\).
- 7 counters are left.
Scoring: 1 point for 11 – 4 = 7. 1 point for the answer 7.
Question 2 – Quick facts [3 pts]
- \(10 – 7 = 3\). The difference is 3.
- \(14 – 5 = 9\). The difference is 9.
- \(12 – 12 = 0\). The difference is 0.
Scoring: 1 point for each correct difference.
Question 3 – Hop back [2 pts]
- \(16 – 6 = 10\).
- The hop ends at 10.
Scoring: 1 point for the sentence 16 – 6 = 10. 1 point for the endpoint 10.
Question 4 – Missing number [3 pts]
- \(15 – 7 = 8\). The missing number is 8.
- \(18 – 9 = 9\). The missing number is 9.
- \(15 – 7 = 8\) (or \(15 – 8 = 7\)).
Scoring: 1 point for each correct part.
Question 5 – Fact family [3 pts]
\(6 + 8 = 14\), \(8 + 6 = 14\), \(14 – 6 = 8\), \(14 – 8 = 6\).
Scoring: 1 point for the two addition facts. 1 point for 14 – 6 = 8. 1 point for 14 – 8 = 6.
Question 6 – How many more? [2 pts]
- The black row has more (13 is more than 9).
- \(13 – 9 = 4\), so 4 more.
Scoring: 1 point for black. 1 point for 4 more.
Question 7 – Apple story [3 pts]
\(16 – 8 = 8\). Diego has 8 apples left.
Scoring: 1 point for choosing to subtract. 1 point for the sentence 16 – 8 = 8. 1 point for the answer 8 apples.
Question 8 – Missing part story [2 pts]
\(12 – 5 = 7\). Check: \(5 + 7 = 12\). 7 cars are green.
Scoring: 1 point for a correct sentence (12 – 5 or 5 + 7 = 12). 1 point for 7 green cars.
Total score
20 points
Key facts behind this subtraction within 20 test answers
- The difference is the answer to a subtraction problem.
- Counting back: hop back from the whole, one number at a time.
- Think addition: 13 – 5 asks what to add to 5 to get 13.
- A fact family uses three numbers, like 8, 7 and 15.
- Subtracting 0 or the whole number gives easy answers: 6 – 0 = 6 and 6 – 6 = 0.
How to use this subtraction within 20 test answers
Score your test with the point values shown for each question. Then read the worked solution of every question where you lost points and note the method to review.
All Grade 1 chapters: Grade 1 math.
