Counting Your Units and Telling Someone the Length

You will meet this idea in ordinary days. Recipes, plans, and prescriptions always name the unit. A number without one is dangerous. This is worth learning because a clear report is as important as a careful measurement. 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.

Here is today’s math treasure. After you lay your units down, count them carefully and say the result as a full sentence: this book is nine cubes long. That sentence gives the object, the number, and the unit, so it can be understood and checked by anybody.

Write it down the same way. Later, when you meet inches and feet, you will already have the habit of always naming what you measured with.

Here is a good habit. Write your measurement down immediately, before you move the units. Numbers held only in your head have a way of changing when you are not looking at them. Take your time. Careful is better than fast.