Deciding Whether a Number Sentence Is True or False

You will meet this idea in ordinary days. Checking claims is a lifelong habit. Wise people test what they are told instead of swallowing it whole. This is worth learning because testing truth carefully is a habit that reaches far past math.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Ask yourself where else the same idea might be hiding, then go and look.

Watch this carefully, friend. Some number sentences tell the truth and some do not. Look at 6 plus 3 equals 9. Add the left side: nine. Compare it with the right side: nine. Both match, so the sentence is true.

Now look at 6 plus 3 equals 10. Nine does not match ten, so that sentence is false. Always figure out both sides separately, then compare. Never assume a sentence is true just because someone wrote it down.

Try making some false sentences on purpose. Write 4 plus 4 equals 9 and explain exactly why it is false: the left side is eight and the sides do not match. Being able to explain why something is wrong shows deeper understanding than only finding right answers. If you get stuck, use your fingers or counters. Good mathematicians use tools.