Addition is a concept that is maybe learnt the first in math, soon after digits. It is not long before they advance to more complex concepts such as multiplications, division, fractions, etc. for them to learn such advanced math concepts, it is imperative for 4th graders to be able to add two digit numbers mentally, in their heads. Mental addition problems form the stepping stone to math that they’ll learn in the higher grades. Download the free mental math printable for the right practice.