Question

how many numbers from 1- 1000 are divisible by both 2 AND 5? Pls help!! @TrashMan914

Answer 1

Hint: to be "divisible by both 2 AND 5" is to be divisible by 2*5 = 10

Answer 2

so just list out the multiples of 10 from 1 to 1000

or you can use the idea that

10 = 10*1
20 = 10*2
30 = 10*3
...
....
980 = 98*10
990 = 99*10
1000 = 100*10

so that will speed up the counting process

Answer 3

so 1000/10?

Answer 4

Oh i guess I should stay consistent

10 = 10*1
20 = 10*2
30 = 10*3
...
....
980 = 10*98
990 = 10*99
1000 = 10*100

Answer 5

can you see how many numbers there are using that trick?

Answer 6

100 thanks! btw if you were to ask for the numbers from 1-1000 divisible by both 6 and 9 would you find the least common multiple of 18? the 1000/18?

Answer 7

yes you would find the LCM of 6 and 9, which is 18, then list out the multiples

Answer 8

do you have to list out the multiples or can you just do 1000/18=55.5? then get 55 as your answer?

Answer 9

that works as well since 55*18 = 990 and that's as high as you can go

so basically

18 = 18*1
36 = 18*2
...
...
990 = 18*55

Answer 10

thank you so much for your help :)

Answer 11

sure thing