IMO Practice Test: Counting Numbers | Class 1 Mathematics

Question 1 of 6

Rohan is counting from 1 to 30. He skips every number that has a 5 in it. How many numbers does he say?

27

24

25

22

Explanation: Numbers with 5: 5,15,25 (3 numbers). 30-3=27. Wait recalc: 5,15,25 = 3 numbers removed from 1-30 (30 numbers total) gives 27. But option A is 27, not B. Correction: Actually 5,15,25 = 3 numbers removed, but also check 50? No, only up to 30. So 30-3=27. Answer is A.

Question 2 of 6

Meera is counting by 2s: 2, 4, 6, 8... She says 10 numbers. What is the LAST number she says?

18

20

22

24

Explanation: Counting by 2s: 1st=2, 2nd=4, 3rd=6, 4th=8, 5th=10, 6th=12, 7th=14, 8th=16, 9th=18, 10th=20

Question 3 of 6

A book has pages numbered from 1 to 50. How many times does the digit '1' appear in the page numbers?

14

15

16

13

Explanation: 1,10,11,12,13,14,15,16,17,18,19,21,31,41 = count '1's: 1 (one '1'), 10 (one), 11 (two), 12-19 (8 more), 21,31,41 (three more) → Total: 1+1+2+8+3=15

Question 4 of 6

Kabir counts backward from 50. He stops when he reaches a number that is a multiple of both 2 and 5. What is the number he stops at?

40

30

20

10

Explanation: Multiples of both 2 and 5 are multiples of 10: 50,40,30,20,10. Counting backward from 50, the last multiple of 10 he reaches is 10

Question 5 of 6

Tina has 7 packets of candies. Each packet has 5 candies. She eats 2 candies from each packet. How many candies are left in total?

35

25

21

14

Explanation: Total candies: 7 × 5 = 35 (count by 5s: 5,10,15,20,25,30,35). Eats 2 per packet: 7 × 2 = 14 (count by 2s: 2,4,6,8,10,12,14). Left: 35-14=21

Question 6 of 6

Which set of numbers follows the pattern: add 3, subtract 1, add 3, subtract 1... starting from 2?

2,5,4,7,6,9,8

2,5,6,9,10,13,14

2,4,7,9,12,14,17

2,5,4,8,7,11,10

Explanation: Start 2: +3=5, -1=4, +3=7, -1=6, +3=9, -1=8 → 2,5,4,7,6,9,8

IMO Practice Test — Counting Numbers