Common Core Math Standards for addition includes the concept of the base 10 system. This includes the idea of counting in fives, tens, and multiples of hundreds, tens, and one, as well as number relationships involving these units. Students will use numbers up to 1000 written in base 10 notation. For example: 941 is 9 hundreds, 4 tens and 1 one.

Common core standards for addition by grade

Kindergarten: Represent the concept of addition and subtraction with objects, fingers, drawings, sounds (clapping),  or numbers. Solve addition and subtraction word problems within the number 10. Decompose numbers less than or equal to 10 into pairs in more than one way. For example 5=2+3 and 5=4+1.  For any number from 1-9  find the number that makes 10  when added to the given number.  Fluidly add and subtract within 5.

1st: Use addition and subtraction within 20 to solve word problems. Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20.  Create equivalent but easier or known sums,  for example: 6+7 is also 6+6+1.

2nd: Use addition and subtraction within 100 to solve one and two step word problems. Add and subtract within 20. By the end of grade 2 your student should know from memory all sums of  two one digit numbers. Work with equal groups of objects to gain the foundations for multiplication. Determine whether a group of objects, up to 20, has an odd or even number of members by pairing objects. Use addition to find the total number of objects arranged in a rectangular array of up to five rows and five columns.

3rd:  Interpret products of whole numbers 5 x 7 as the total number of objects in five groups of seven objects each. Interpret  whole number quotients 56 divided by 8 as the number of objects in each share when 56 objects are partitioned equally into eight shares. Use multiplication and division within 100 to solve word problems in situations involving equal groups.