How can undefinable terms be used to create precise mathematical definitions?

Rai compares two cable plans from different companies. which equation gives the correct value of mm, the number of months for which plans a and b cost the same?

Noor brought 21 sheets of stickers. she gave 1/3 of a sheet to each of the 45 students at recess. she wants to give teachers 1 1/2 sheets each.

Write the fraction 9/50 as a decimal if needed round to the nearest hundredth