Students whose answers fit into the above common error categories have an arithmetical view of the meaning of the equals sign. To them equals only means "and the answer is". This is particularly true of the first group of common errors. Students need to understand that the expression on the left-hand side of the equals sign represents the same quantity as the expression on the right-hand side of the equals sign, or that "=" means "the same as". Initiating a discussion about the meaning of the equals sign is a starting point in coming to understand this concept. Resource Equality uses true/false number sentences to generate discussion about the meaning of the equals sign.
Exposing students to a variety of ways in which number sentences can be written, e.g., 5 = 4 + 1, 6 = 6, 9 = 1 + 3 + 5 etc. can help students see that the equals sign does not always come at the end of the number sentence.

The concept of equals as meaning both sides of the equation represent the same quantity can be introduced through the concept of balancing equations. Use simple balance pan scales and coloured multi-blocks to visually represent simple open number sentences/equations. See resource Balance pans for further examples.
The Algebraic thinking concept map has further information on the concept of equality and the idea of closure.

For students who have grasped the idea of equality, try more challenging number sentences using larger numbers that promote relational thinking. Use numbers on each side of the equation that are only a few digits away from each other and encourage the students to explore the relationships between the numbers rather than perform calculations, e.g.,
58 + 13 =  + 15     15 is 2 more than 13, so the answer in the box is 2 less than 58 (i.e., 56)
12 + 78 = 16 +       16 is 4 more than 12, so the answer in the box is 4 less than 78 (i.e., 74)
213 + 62 = 65 +       65 is 3 more than 62, so the answer in the box is 3 less than 213 (i.e., 210).