To find the prime factors, start with the obvious ones. 4914 is even so divide it by 2 and we get 2457. The digit sum of this is 9, so divide by 9 (3x3) and get 273. The digit sum divides by 3 so divide by 3 and get 91, which is 13x7. So in total we have 2, 3, 3, 3, 7 and 13 as the prime factors of 4914
Divide by 3, 7 and 13. 1, 3, 7, 13, 21, 39, 91, 273
7 + 9 + 11 = 27. Divide by 3. = 9.
177.5
(51/3) / (13/4) = (16/3) / (7/4) = (16/3) * (4/7) = 64/21
To find the prime factors, start with the obvious ones. 4914 is even so divide it by 2 and we get 2457. The digit sum of this is 9, so divide by 9 (3x3) and get 273. The digit sum divides by 3 so divide by 3 and get 91, which is 13x7. So in total we have 2, 3, 3, 3, 7 and 13 as the prime factors of 4914
Divide by 3, 7 and 13. 1, 3, 7, 13, 21, 39, 91, 273
728 Divide by two. 364,2 Divide by two. 182,2,2 Divide by two. 91,2,2,2 Divide by seven. 13,7,2,2,2 Stop.
The smallest 3-digit multiple of 7 is 105 = 15*7 The largest 3-digit multiple of 7 is 994 = 142*7 So there are 142-14 = 128 3-digit multiples of 7, ie 128 3-digit numbers that are divisible by 7.
7 + 9 + 11 = 27. Divide by 3. = 9.
2506 2506 is divisible by 7. (6 is 3 times of 2; 2+5+0+6=13; 5=6–1)
All 2 digit numbers are divisible by 7: it is simply that some of the quotients are not whole numbers. 10/7 = 1 3/7 99/7 = 14 1/7 So the number of 2-digit numbers which are evenly divisible by 7 are 14-1 = 13.
The highest four digit number with 13 and 7 as common factors is 9919, which is equal to 13 x 763 and 7 x 1417.
7
-7
(51/3) / (13/4) = (16/3) / (7/4) = (16/3) * (4/7) = 64/21
1, 2, 3, 5, 6, 7 and 9