1. Find the multiples of 7 which is greater than 56 but less than 77. 2. List all the common factors of the following: (i) 12,18,21 (ii) 20,40,35 (iii) 16,18,7 3. Write all prime numbers between 70 and 90. 4. Write the following numbers as a product of their prime factors: (i) 70 (ii) 105 (iii) 91

1. Find the multiples of 7 which is greater than 56 but less than 77.

1.	1. Find the multiples of 7 which is greater than 56 but less than 77. 2. List all the common factors of the following: (i) 12,18,21 (ii) 20,40,35 (iii) 16,18,7 3. Write all prime numbers between 70 and 90. 4. Write the following numbers as a product of their prime factors: (i) 70 (ii) 105 (iii) 91
Answer» -step explanation:1. MULTIPLES of 7 = 56 < (63, 70) < 772. (i) FACTORS of 12 = 1, 2, 3, 4, 6, 12 Factors of 18 = 1, 2, 3, 6, 9, 18 Factors of 21 = 1, 3, 7, 21 Common factors = (1 , 3) (ii) Factors of 20 = 1, 2, 5, 10, 20 Factors of 40 = 1, 2, 4, 5, 8, 10, 20, 40 Factora of 35 = 1, 5, 7, 35 Common factors = (1 , 5) (iii) Factors of 16 = 1, 2, 4, 8, 16 Factors of 18 = 1, 2, 3, 6, 9 Factors of 7 = 1, 7 Common factors = (1 , 7)3. (71, 73, 79, 83, 89)4. (i) 70 = (2×5×7) (ii) 105 = (3×5×7) (iii) 91 = (7×13)