First, try to factor the numerator into a product using the 10-times table (extended with 11), then use division to check whether the denominator can be divided without remainder by one of the factors in the product formed from the numerator. If yes, then, knowing the quotient, also factor the denominator into a product. If it is not divisible, then do the same the other way around! Factor the denominator into a product using the 10-times table (extended with 11), then use division to check by which factor of the product formed in the denominator the numerator is divisible; then, knowing the quotient, also factor the numerator into a product! In the next step, simplify the fraction!