Model 3+(-4) on the number line

Can someone pls ! pls answer all. no explanation needed..

Suppose that in 2008 , 840,800 citizens died of a certain disease assuming the population of teh country is 399 miliion, what is the mortality rate in units of deaths per 100,000 people?

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4