This activity has 40 math riddles that involve mental math computation with 2 numbers and 1 operation (i.e. take the number of hours in a day and less the number of sides in 3 triangles.) These exercises are intended to strengthen students' mental math skills by reading aloud the riddle to the students and having the students compute the answer without paper, pencil, or a calculator. Included is a teacher copy that has all the riddles and the answers and 40 colorful task cards with the same riddles that can be used in centers or for students to read aloud to one another. This edition is the first of three levels. The second level is a free edition and has riddles that involve 3 numbers and 2 operations. The third level may also be purchased and has riddles that involve 4 numbers and 3 operations. The varying levels makes differentiation easy.