中文（繁體）
中文（简体）
English
Primary 1 Maths: Addition and Subtraction within 20 and 100 — Practice Paper 4 (10 Questions)
Primary 1 Maths: Addition and Subtraction within 20 and 100 — Practice Paper 4 (10 Questions)
Paper 4 is built on doubles: 7 + 7 and 8 + 8 first, then a near double and a subtraction read straight off a double, two fresh column questions (carry and borrow), a missing starting number, repeated subtraction and change from three purchases. The last two items target “borrowed one but left the tens alone”.
Quick answer 10 questions, about 20 minutes. Items 01 to 03 are doubles, a near double and a subtraction read off a double; items 04 to 07 are a column carry, a column borrow, a missing starting number and two subtractions in a row; items 08 and 09 are change from three purchases and spotting the bad step; item 10 redoes the ones digits subtracted the wrong way round.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 questions |
| Suggested time | 20 minutes |
| Difficulty mix | Foundation 3 · Intermediate 4 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: Primary 1 Maths: Addition and Subtraction within 20 and 100 — Tutor Lesson Plan |
| Level | Primary 1 |
02 Questions (10 items)
- FoundationWork out: 7 + 7 and 8 + 8.
- FoundationUse a double: 8 + 9 (hint: 8 + 8 = 16 and 9 is one more than 8)
- FoundationWork out: 18 − 9 (hint: 9 + 9 = 18)
- IntermediateWork out in columns: 67 + 25
- IntermediateWork out in columns: 81 − 46
- IntermediateA number minus 29 equals 46. What is the number?
- IntermediateWork out: 90 − 27 − 18 (in two steps)
- ChallengeYou take $100 and buy three things costing $26, $19 and $18. How much change?
- ChallengeMei works out 93 − 68 and answers 35. Which step went wrong, and what is the right answer?
- Error redoWork out in columns: 74 − 6 (common slip: doing 6 − 4 = 2 in the ones and answering 72)
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 14 and 16 | Adding a number to itself is a double: two 7s make 14 and two 8s make 16, and these should come out without counting. |
| 2 | 17 | 9 is 1 more than 8, so 8 + 9 is the double 16 plus 1: 16 + 1 = 17. |
| 3 | 9 | 18 is two 9s, so taking one 9 away leaves 9, and 9 + 9 = 18 checks it. |
| 4 | 92 | Ones: 7 + 5 = 12, write 2 and carry 1. Tens: 6 + 2 + 1 = 9, so 92. |
| 5 | 35 | Ones: 1 cannot take 6, so borrow to make 11 − 6 = 5. Tens: 8 drops to 7 and 7 − 4 = 3, giving 35. |
| 6 | 75 | The starting number is the biggest, so add back: 46 + 29 = 75, and 75 − 29 = 46 checks it. |
| 7 | 45 | First 90 − 27 = 63, then 63 − 18 = 45; the two amounts together are 27 + 18 = 45 and 90 − 45 is 45 again. |
| 8 | $37 | The three cost 26 + 19 + 18 = 63 in all, then 100 − 63 = 37, and 37 + 63 = 100 checks it. |
| 9 | The tens were not reduced after borrowing; the answer is 25 | Ones: 3 cannot take 8, so borrow and 13 − 8 = 5. Tens: 9 loses the borrowed 1 and becomes 8, and 8 − 6 = 2, giving 25. Mei kept 9 − 6 = 3 in the tens, which is 10 too many. |
| 10 | 68 | Ones: 4 cannot take 6, so borrow to make 14 − 6 = 8; the tens drop from 7 to 6, so the answer is 68, not 72. In subtraction the larger digit is never taken from the smaller one. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
