IMO Practice Test — Comparing, Ordering & Rounding
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
hard
Three numbers in a row (consecutive) add to 99. The smallest is…
32
33
31
30
Explanation: 32 + 33 + 34 = 99, so the smallest is 32.
Question 2 of 6
hard
I am greater than 2,500 and less than 2,510, even, and I end in 4. Who am I?
2,502
2,504
2,514
2,524
Explanation: Between 2,500 and 2,510 ending in 4 → 2,504.
Question 3 of 6
hard
What is the greatest whole number that rounds to 50 (nearest 10)?
54
55
59
44
Explanation: 54 rounds to 50; 55 rounds up to 60.
Question 4 of 6
medium
What number is just before 50,000?
49,999
50,001
49,990
40,999
Explanation: One less than 50,000 is 49,999.
Question 5 of 6
hard
What is the smallest whole number that rounds to 100 (nearest 100)?
50
51
49
149
Explanation: 50 rounds up to 100; 49 rounds down to 0? (nearest 100 → 0).
Question 6 of 6
hard
Which is greater: 4 ten-thousands or 40 thousands?
4 ten-thousands
40 thousands
equal
cannot tell
Explanation: Both equal 40,000.