Arithmetic quiz

More questions about Arithmetic

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   What term describes a whole number greater than 1 with only two factors?

   Answer: Prime number

   Why: Euclid proved around 300 BC that there are infinitely many prime numbers, a foundational result in number theory.

2. 2 Medium

   What is the decimal equivalent of the fraction $\frac{1}{8}$?

   Answer: 0.125

   Why: For 205 years Wall Street quoted share prices in eighths of a dollar, so the smallest tick was worth twelve and a half cents.

3. 3 Hard

   Which four-digit constant results from repeatedly subtracting rearranged digits?

   Answer: 6174

   Why: D. R. Kaprekar's 1949 routine: order the digits high then low, subtract, repeat. Any four digits that are not all equal reach it within seven rounds.

4. 4 Easy

   Which number is the only one without a Roman numeral equivalent?

   Answer: zero

   Why: Around 725 Bede or a colleague used N, for nulla, in a Roman numeral table, the closest the system came to a zero sign.

5. 5 Medium

   What do the opposite sides of a standard six-sided die always sum to?

   Answer: seven

   Why: Medieval European dice often paired consecutive numbers on opposite faces, and the sevens layout only took over around 1450.

6. 6 Hard

   What is the smallest positive integer divisible by every number from 1 to 10?

   Answer: 2520

   Why: With 48 divisors, more than any smaller whole number, 2520 is what Ramanujan named a highly composite number.