Science quiz
Highest common factors
For each pair, type the largest number that divides both exactly. Twenty pairs, with Prev and Next to skip.
- Format
- Type them all
- Items
- 20 answers
- Limit
- 3:00
- Level
- Medium
- Checked
- 2026.10.03
- Answers
- 20
- Time limit
- 3:00
- Order
- One at a time, skip allowed
- Matching
- Case and accents ignored
- The highlighted slot is the one to answer.
- Prev and Next skip around; click a slot to jump to it.
- Enter on an empty box skips; the up and down arrow keys step through the slots.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
Type the highest common factor of each pair.
About this quiz
The highest common factor, also called the greatest common divisor, is the largest whole number that divides two numbers exactly. It is what you divide by to put a fraction in its lowest terms.
- Euclid's algorithm finds it by repeated remainders, and is more than 2,000 years old.
- No pair here has a highest common factor of 1.
- Dividing 24 and 36 by their highest common factor, 12, turns 24/36 into 2/3.
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