IMO Practice Test — Multi-Digit Multiplication
6 Questions • 25 min • Olympiad level
25:00
Question 1 of 6
hard
99 × 11 = ?
1089
1099
1189
990
Explanation: 99 × 11 = 99 × 10 + 99 = 990 + 99 = 1089.
Question 2 of 6
medium
Estimate 89 × 89 to the nearest 10.
8100
8000
9000
6400
Explanation: ≈ 90 × 90 = 8100.
Question 3 of 6
hard
A water tank fills 125 litres per hour. How much in a full day (24 hours)?
2500 L
3000 L
3600 L
1250 L
Explanation: 125 × 24 = 3000 litres.
Question 4 of 6
hard
A rough estimate of 612 × 8 is…
about 4800
about 5600
about 4000
about 6400
Explanation: ≈ 600 × 8 = 4800 (exact 4896).
Question 5 of 6
hard
Which gives the largest product?
20 × 30
25 × 25
10 × 60
40 × 15
Explanation: 25 × 25 = 625; the others all equal 600.
Question 6 of 6
hard
A school orders 36 boxes of chalk with 144 sticks each. How many sticks in all?
5184
5084
5200
4184
Explanation: 144 × 36 = 5184.