Equals means equals!

I have observed several students and notes from teachers writing incorrect maths statements when using the 'tidy numbers' method. They get the right answer but they write mathematically incorrect statements with the use of the equals sign. Here is an example:

28 + 44 28 + 2 = 30 + 42 = 72

28 + 2 = 30 but then they add on the other numbers and incorrectly string additions resulting in 30=72.

This is potentially problematic for learning algebra in later years where manipulation of algebraic expressions is fundamental. "What you do on one side of the equation, must also be done to the other side of the equation so that the equation remains equal (and valid). Equals means equals!

I would prefer correct maths statements be taught from the outset:

28 + 44 = 28 + 2 + 44 - 2 = 30 + 42 = 72

Or 28 + 44 = 20 + 8 + 40 + 4 = 60 + 12 = 60 + 10 + 2 (optional) = 70 + 2 = 72

These 'grouping' techniques give students a good grasp of the decimal number system and are great for mental calculations, however for larger numbers there is no going past column addition!