Balancing Both Sides: Why 5 Plus 3 Equals 6 Plus 2

This idea walks around your house all day. A balance scale holds real weight on both pans. Adding to one side means you must add to the other to stay level. This is worth learning because balancing both sides is how equations work for the rest of your life. Watch for it today, and when you spot it, tell someone what you noticed and how you knew.

This is a good thing for a young mathematician to know. Both sides of an equal sign can hold addition. Look at 5 plus 3 equals 6 plus 2. The left side makes eight and the right side makes eight, so the sentence is true.

Add each side separately, then compare the two totals. Notice something interesting: the right side took one from the three and gave it to the five. Moving an amount from one number to the other keeps the total the same.

Here is the trap. Some people see 5 plus 3 equals 6 plus 2 and write eight in the middle somewhere. There is no middle answer to write. Compute each side separately and simply decide whether the sentence is true. Do it carefully rather than quickly, and thank God for a mind that can learn.