Answer:
Bottom box= 103/210
Middle-right box=19/30
Middle-left box=7/21
Explanation:
we can convert 1/7 to 21ths so it will be easier to add.
1/7 = 3/21
so, 3/21 + 4/21 = 7/21
we can now use that to find the box next to it.
The LCM (lowest common multiple) of 21 and 30 is 210.
7/21 = 70/210
29/30 = 203/210
so 203/210-70/210 = 19/30 (simplified)
and finally, we can use this to work out the fraction in the bottom box.
LCM of 30 and 7 is also 210.
so 1/7 = 30/210
19/30 = 133/210
so 133/210 - 30/210 = 103/210.