Joshua's family took a road trip to Mount Rushmore. Joshua fell asleep 35% of the way through the trip. If the total length of the trip was 400 miles, how many miles had they travelled when Joshua fell asleep?

You need to calculate 35% of 400.

The way I do this on paper is I split it up into chunks and then add the chunks together.

First I would calculate 10%. To do this, divide 400 by 10, because to get from 100% to 10% you must divide by 10.

So 10% = 40

You need 30%, so you just multiply by 3, because to get from 10% to 30%, you multiply by 3.

So 30% = 120

5% is half of 10% so half of 40 is 20.

So 5% = 20

30% + 5% = 35%

120 + 20 = 140

So they had traveled 140 miles when Joshua fell asleep. Hope this helps :)