New Learning Composite Mathematics SK Gupta Anubhuti Gangal Class 6 Playing With Numbers Self Practice 3D Solution
(1) 12= 5+7
(b) 30= 11+19
(c) 68= 31+37
(d) 72= 31+41
(2) (a) 12= 5+7
(b) 30= 13+17
(c) 78= 37+41
(d) 90= 47+53
(3) (a) 15 = 3+5+7
(b) 23= 5+7+11
(c) 35= 5+7+23
(d) 55= 13+19+23
(4) The five pairs of prime numbers less than 20, whose sum is divisible by 5 —
(2,3) , (3,7), (2,13), (3,17) and (13,17).
(5) (a) 151 is divisible by 1 and 151 , so it is a prime number.
(b) 69 is divisible by 1, 3, 2, 69 ,so, it is not a prime number.
(c) 241 is divisible by 1 and 241 so, it is a prime number.
(d) 265 is divisible by 1, 5, 53, 265 so it is not a prime number.
(6) The tree prime numbers are 5, 7 and 11
5x7x11= 385
(7) F
Eg- 8 and 15 are co-prime numbers, but none is a prime number.
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