Math Riddles

Question: can you make an equation by using only the no.-4,4,4,4 whose answer will be 20.

Question: 1 11 21 1211 111221 312211 13112221 1113213211 what comes next?

Question: someone came into my shop and stole 100 dollars from the register without my knowledge. the person came back 5 minutes later with the same 100 dollars and bought 70 dollars in items and i gave him back 30 dollars change. How much did i lose?

Question: I'm 10 years old my brothers half my age now I'm 100 years old how old is my brother now?

Question: A son's age is the age of his dad's age's digits added together. The son is not nine or older. The dad is of legal age. The dad's age doesn’t end in a zero, and is more than twenty, but less than twenty-five. How old is the dad, and how old is the son?