Luis rode his bike 1.2 miles to his friend's house, then 0.7 mile to the video store, then 1.9 miles to the library. if he rode the same route back home, about how far did he travel in all?

Start by rounding each of the numbers you're working with. Round 1.2 down to 1. Round. 7 up to 1. Round 1.9 up to 2. So Luis rode his bike about 1 mile to his friend's house, then about 1 mile to the video store, then about 2 miles to the library. Add the numbers together to find out how far he traveled from his house to his friend's house to the video store to the library. 1 + 1 + 2 = 4, so he rode about 4 miles. If he rode the same route back home, then multiply that by 2, since he traveled the same distance twice. 4 x 2 = 8. So Luis traveled about 8 miles in all.