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

   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.

2. 2 Medium

   Which property allows regrouping numbers without changing the sum?

   Answer: Associative property

   Why: The associative property changes how terms are grouped with parentheses, whereas the commutative property changes their order.

3. 3 Hard

   What is the horizontal bar separating beads on a Chinese abacus called?

   Answer: Reckoning bar

   Why: Above the bar sit the heaven beads, worth five each; below are the earth beads; UNESCO listed Chinese abacus arithmetic, zhusuan, in 2013.

4. 4 Easy

   What is the sum of interior angles in any triangle?

   Answer: 180°

   Why: On a globe the rule fails: a triangle drawn on that curved surface has angles adding up to more than 180 degrees.

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

   Which number is the smallest Hardy-Ramanujan 'taxicab' number?

   Answer: 1729

   Why: Hardy rode that cab to Ramanujan's Putney nursing home in 1919, and a plaque at 2 Colinette Road now marks the house.