IMPORTANT!  Please READ!  

Parents, please do not show your children the algorithm (aka the "short cut" method or  "traditional method") before their classroom teachers provide instruction.   

It makes learning the concept of addition and subtraction much more difficult if your children do not understand the "why" before the "how."  It also makes it more difficult for your child to mentally decompose (break apart) numbers so they can calculate more complex equations and fractions "in their head."