What is the sum of all natural numbers within 100 that are not multiples of 3?
1+2+4+5+7+8+.+97+98
=(1+4+7+.+97)+(2+5+.+98)
=(1+97)*33/2+(2+98)*33/2
=198*33/2
=3267
How many natural numbers within 100 are not multiples of 3
100 / 3 ≈ 33
100-33 = 77
There are 77 natural numbers within 100 that are not multiples of 3
In natural numbers from 1 to 100, there are______ The number is not a multiple of 3 or 5
The multiples of 3 are: 100 / 3 ≈ 33 (pieces), and the multiples of 5 are: 100 / 5 = 20 (pieces). The number of multiples of 3 and 5 (that is, the common multiple of 3 and 5) is: 100 / 15 = 6 (pieces). Therefore, the number of multiples of 3 or 5 is: 33 + 20-6 = 47 (pieces), and the number of multiples that are neither multiples of 3 nor multiples of 5 is: 100-47 = 53 (pieces). Therefore, the answer is: 53