Calculating Monthly Premium rates base on age

Attached is sheet that I want to use to calculate monthly premium rates based on applicants age over 1,3,4,5, and 10 year terms (see "Assurant" tab). I have figured out how to calculate for one age group (i.e. 51-60) using the IF statement, but don't know how to add a multi-string to accomidate all the other age groups. Can I do this with IF or is there anouther formula I should be using?