1st Grade Math: Be aware of the communative property.
At this age kids need to know that it doesn't matter if you add 4+3 or 3+4 it will be the same. They also need to know that it doesn't work with subtraction.
2nd Grade Math: Understand and explain the communative property.
At this age kids need to be able to explain why 4+3 or 3+4 are the same. For example, using objects they can demonstrate how you can flip flop addition ( it is obviously always the same amount) and why subtraction won't work.
Just for your information....
There are four math properties which involve addition. These math properties are the commutative, associative, additive identity and distributive properties.
Commutative property: When two numbers are added, the sum is the same regardless of the order of the addends. For example 4 + 2 = 2 + 4
Associative Property: When three or more numbers are added, the sum is the same regardless of the grouping of the addends. For example (2 + 3) + 4 = 2 + (3 + 4)
Additive Identity Property: The sum of any number and zero is the original number. For example 5 + 0 = 5.
Distributive property: The sum of two numbers times a third number is equal to the sum of each addend times the third number. For example 4 * (6 + 3) = 4*6 + 4*3
Although your child doesn't need to know all of these; it is important to know that it is one of these essential properties your child will learn in the future.