Your students will love the fun of solving riddles for unknown numbers in addition equations! These easy prep riddle task cards plus printables are a great way to practice solving for a missing addend for sums within 20.How these riddles work:Choosing from four numbers on each card, your students will solve for the missing addends to eliminate three of the options. With each riddle they complete, your students will solve three missing addend number models by adding on or by subtraction– that