3rd Grade Math Worksheet Addition | Math worksheets, 3rd grade math ... This third grade math worksheet will help children learn how to add two and three digit numbers. There are 16 addition problems for third graders to solve. Thir. ... Description The set has 20 animal-themed worksheets to practice 3-digit addition without regrouping. Sheets are neatly formatted. ~~Answer keys are included.~~ Use for morning work ...