My son was in Kindergarten last year and yes they do learn simple addition in kindergarten. As a matter of fact he in in 1st grade now and bringing home double didgit subtraction and addition. He WILL catch on to the math. An easy way to get him to grasp the concept is to use visual manipulatives. such as mini marshmallows or goldfish crackers and in addition he'll get an afternoon snack while doing homework. for example if the math problem is 6+3= have him start with 6 marshmallows and explain in simple terms why, and have him add 3 more marshmallows to the six. then ask him how many he has all together. If he continues to do his math in the manner he will eventually grasp the idea and he won't need the manuulatives anymore. Do the same with subtraction. It worked for me and I think it will work for you too. good luck.