Worksheet on Playing with Numbers

This section is based on Worksheet on Playing with Numbers.
Q1. Find the multiples of 7 which is greater than 56 but less than 77
Q2.Give at least common multiple of the two numbers.
(i) 3,9
(ii) 2,9
(iii) 4,6
(iv) 8,10
Q3. List all the common factors of the following:
(i) 12,18,21
(ii) 20,40,35
(iii) 16,18,7
Q4. Match the items in column I and column II.
(i)45         (A) multiple of 3
(ii)15         (B) factor of 40
(iii)24         (C) multiple of 7
(iv)20         (D) factor of 30
(v)35         (E) multiple of 9
Q5.Sort out even and odd numbers: 43, 48, 61, 69, 80, 155, 332, 264, 89, 19, 76, 125, 64
Q6. Express each of the following numbers as the sum of three odd prime numbers
(i) 31
(ii) 35
(iii) 49
(iv) 63
Q7. Write all prime numbers between 70 and 90.
Q8. Using divisibility test, determine which of the following numbers are divisible by 2; by 3; by 4; by 5; by 6; by 8; by 9; by 10; by 11.
Q9. Arrange the prime factors of 3350 in ascending order.
Q10. Use prime factorisation to find the H.C.F of the following:
(i) 70, 105, 175
(ii) 91, 175, 49
(iii) 66, 330
(iv) 34, 102
Q11. Find the L.C.M of the following by prime factorisation method:
(i) 42, 63, 162
(ii) 42, 78, 104, 112
(iii) 16, 28, 40, 77
(iv) 112, 168, 228
Q12. Find the greatest length of the rod which can measure exactly 42m, 49m and 84m. Find also the number of times the rod is contained in each length.
Q13. Telegraph poles occur at equal distances of 220 m along a road and heaps of stones are put at equal distances of 300 m along the same road. The first heap is at the foot of the first pole. How far from it along the road is the next heap which lies at the foot of a pole?
Q15. The length breadth and height of a room are 8 m 25 cm, 6 m 75 cm and 4 m 50 cm, respectively. Determine the longest tape which can measure the three dimensions of the room.
Q16. Find the greatest number such that if 285 and 1249 be divided by it, leaving the remainder 9 and 7 respectively.
Q17. Find the least number which when divided by 12, 15, 36 and 45 leaves in each case remainder 4.
Worksheet on playing with numbers

Answers of Playing with Numbers