The ration for lawns to hours is 4 lawns :7 hours simplified to .57 lawns :1hour or 7 hours :4 lawns simplified to 1.75 hours:1 lawn
A ratio is a number compared to another for example
2 eyes:1 human
7 days:1 week
It's usually simplified to have the right number 1 so you can see how many 1 of the right is in relation to the left. To simply you can just divide the 2 #s like a fraction