I know this is a hard one but I need this step by step 4 times 66+17867.94-21,196.18 divided by 260 times 66 + 17867.94 + 1538,000,000,000 divided by 66

How to do this , and can some one explain

Select all the expressions that will include a remainder.

Answer asap ill give ! ’ a sample of radioactive material decays over time. the number of grams, y , of the material remaining x days after the sample is discovered is given by the equation y = 10(0.5)^x. what does the number 10 represents in the equation? a. the half-life of the radioactive material, in days b. the amount of the sample, in grams, that decays each day c. the time, in days, it will take for the samples to decay completely d. the size of the sample, in grams, at the time the material was discovered