IMO Practice Test — Comparing, Ordering & Rounding
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
medium
A number rounds to 700 (nearest 100). Which could it be?
740
760
650
660
Explanation: 740 rounds to 700; 760 rounds to 800.
Question 2 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 3 of 6
medium
Make the greatest 5-digit number using 3, 0, 7, 1, 9 (each once).
97,310
97,130
93,710
73,910
Explanation: Biggest digits first: 9, 7, 3, 1, 0.
Question 4 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 5 of 6
hard
Which list is correctly ordered SMALLEST to LARGEST?
9,899; 9,900; 9,989
9,989; 9,900; 9,899
9,900; 9,899; 9,989
9,989; 9,899; 9,900
Explanation: 9,899 < 9,900 < 9,989.
Question 6 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.