Giải toán định lượng và dữ liệu
Đã giới thiệu| English | Ý nghĩa |
|---|---|
| numeric entry/njuːˈmerɪk ˈentri/ | A Quant question type in which you type the answer instead of choosing it. |
| average/ˈævrɪdʒ/ | The sum of the values divided by how many values there are. |
Calculator on screen, answer in a box
- A GRE question asks for a percentage and gives a box to type the answer; another asks you to select all values that satisfy a condition.
- Quantitative problem solving mixes algebra, geometry and data, and the answer format matters as much as the maths.
Three formats
- Single-answer multiple choice: choose one. Multiple-answer: select every correct option — there may be one, several or all.
- Numeric entry 数字填空: type a number (or a fraction in two boxes); follow instructions about rounding and units.
Which answer format?
Recognise GRE quantitative answer formats.
Work the problem cleanly
- Translate words to equations: "15% more than $x$" → $1.15x$. "The average 平均数 of 5 numbers is 12" → their sum is 60.
- Use the on-screen calculator for arithmetic, but set up the algebra yourself.
A shirt costs $40 after a 20% discount. Original price: $0.8p = 40$, so $p = 50$ dollars. Not $40 \times 1.2 = 48$.
A jacket costs $72 after a 10% discount. What was the original price in dollars?
Độ khó 2/5 · 140 xu + một phần thưởng nhỏ cho lần hoàn thành đầu tiên trong ngày
$0.9p = 72$, so $p = 80$.
The average of 4 numbers is 15. Three of them are 10, 12 and 20. What is the fourth?
Độ khó 2/5 · 140 xu + một phần thưởng nhỏ cho lần hoàn thành đầu tiên trong ngày
Sum = 60; 60 − 42 = 18.
“15% more than x” can be written as ____x.
Độ khó 1/5 · 100 xu + một phần thưởng nhỏ cho lần hoàn thành đầu tiên trong ngày
100% + 15% = 1.15.
Select-all questions
- Test each option separately against the condition; do not stop after the first correct one.
- Example: which of 2, 3, 4, 6 divide 48 and 30? 2 ✓, 3 ✓, 4 ✗ (30), 6 ✓.
Which numbers divide both 48 and 30? Select all that apply.
Độ khó 2/5 · 140 xu + một phần thưởng nhỏ cho lần hoàn thành đầu tiên trong ngày
2, 3 and 6 divide both; 4 and 8 do not divide 30.
Common traps
- Undoing a percentage change with the opposite percentage (−20% is not undone by +20%).
- Selecting only one option in a select-all question.
A price that falls by 20% returns to its original value after a 20% increase.
Độ khó 1/5 · 100 xu + một phần thưởng nhỏ cho lần hoàn thành đầu tiên trong ngày
0.8 × 1.2 = 0.96.
Recap
- Translate words into equations carefully; use averages as sums.
- Check the answer format: one, several, or a typed number with the required form.
- numeric entry: A Quant question type in which you type the answer instead of choosing it.
- average: The sum of the values divided by how many values there are.