Using Counters, Ten Frames, and Number Lines to Track Down a Missing Number

Think about where you have seen this before. Different jobs use different measuring tools, but a true measurement is a true measurement no matter which tool found it. This is worth learning because when one tool confuses you, another usually clears it up.

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.

Take a deep breath and look at this. Tools help with blanks. With counters, build the whole, pull out the part you know, and count what remains. With a ten frame, fill in the known part and count empty squares.

With a number line, put a finger on the part and hop up to the whole, counting hops. Three different tools, one answer. Pick the one that makes the amounts easiest for your eyes to see.

Try one problem with all three tools and see which one you reach for first. Different people find different tools clearest, and knowing your own preference is useful. But be able to use all three, since one may not be handy when you need it. When you get it right, say thank You to God, who gave you that thinking mind.