First of all, let's calculate how many kilometers a road worker can repair every day, that is, 2/ 10, that is, 0.2 kilometers a day, 1 day =0.2 kilometers, that is, 18/0.2 kilometers, that is, it will take 90 days to repair.

This is the application of primary school mathematics (normalization method). First, find out how long it takes workers to close the road every day: 2km/10 = 0.2km. The time required to find out 18km: 18km/0.2km =90 days. If you are older, you can divide it by 2/ 18 = 90 days.

Reference: I

18 divided by 2X 10 =6X 10 =60 (days) because 2X? = 18 = 18 divided by 2 X=6 6X 10 is because the road was built on 10 for 2km. Sorry about x10 2007-1-13/.

I miscalculated left 18 divided by 2, and the sequence =9.

Reference: I

I know. First, 2 kilometers is equal to 2000 meters, so it takes 10 days to build a road, which means that 2000 is divided by 10, which means that 200 meters of roads are built in one day. Now we need to build roads 18km, 18km, that is 18000m, 200m a day, that is, we need to build roads a day. 2 kilometers, the bar system 18000 divided by (2000 divided by 10) equals 90 days.

18÷(2÷ 10) =90 (days) Definition: 18 days ÷(2km ÷ 10 days) 2km divided by 10 days =

18÷2× 10 =9× 10 =90 10÷2× 18 =5× 18 =90 10÷2

It can be calculated that it takes several tons to build roads 1 km.

Then × 18, we know how resistant it is to 18 km.

10 day, 2km, 90km, 18km, Hao ~ (1 0/2) (18) = 5 (18) = 90. You ask for the left10. Then take a bus back to18lor ... 2007-11318: 40: 45. Supplement: You are a junior four, wor ... You can't make a list, but you should: (/kloc.