10=5*2
9= 3*3
8= 2*2*2
7= 7
6= 3*2
5= 5
4= 2*2
3= 3
2= 2
1= 1
We need a product that include all of the combinations in the right column.
Starting from the top:
10 gives us: 5*2
9 gives us: 3*3
8 gives us: 2*2 (we already have the third 2)
7 gives us: 7
6 gives us: nothing (we already have both a 2 and a 3)
5 gives us: nothing
4 gives us: nothing
3 gives us: nothing
2 gives us: nothing
1 gives us: 1 So: 5*2*3*3*2*2*7*1=2520. There is no number between 1 and 2000 that fits.
48 has the most factors; it has 10 factors: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
The number 10 can be the product of 2 and 5, 1 and 10. This means that 10 has 4 factors. :]
11
A multiple is found by multiplying the number. Whereas a factor is what the number can be divided by. For example - multiples of 10 are; 10, 20, 30, 40, ... Factors of 10 are; 1, 2, 5, 10
Four
2555
12
48 has 10 factors.
The numbers between 10 and 30 that have exactly 5 factors are 16 and 25. The number 16 has factors 1, 2, 4, 8, and 16. The number 25 has factors 1, 5, 25, but since it is a perfect square, it also includes the repeated factor of 5. These are the only two numbers between 10 and 30 that have exactly 5 factors.
5, 10, 15 and 20 have five as a factor. The number 16 has five factors.
3 x 4 = 12
16, with factors 1, 2, 4, 8 and 16.
There are no factors of 10 between 20 and 100.
6, 8, 10, 14, 15
48 has the most factors; it has 10 factors: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
Any number between 30 and 40 can be a factor. The common factors of 30 and 40 are 1, 2, 5 and 10.
Subtraction of 10 from 2000 gives the required number. 2000 - 10 = 1990 is 10 less than 2000.