NC.1.oa.7

First grade students are expected to write equations and use informal language to explain the meaning of equations where the equal sign is a symbol that means “one side of the equation has the same value as the other side of the equation.” 

Students should explore the concept of "equal sides" using concrete materials (manipulatives) and drawings in the context of joining groups of objects (addition) and separating/taking away a group of objects (subtraction). 

When students understand that an equation needs to “balance”, with equal quantities on both sides of the equal sign, they understand various types of equations, such as: 

• operation on left side of the equal sign, and answer on right side (5 + 8 = 13) 

• operation on right side of the equal sign and answer on left side (13 = 5 + 8) 

• only numbers on both sides of the equal sign (6 = 6) 

• operations on both sides of the equal sign (5 + 1 = 9 - 3). 

Once students understand the meaning of the equal sign, they are able to determine if an equation is true (9 = 9) or not true (9 = 8).