Using an Addition Fact You Know to Solve a Subtraction Fact
What career does this lesson unlock?
Adelaide will match a real-world profession to what you just learned and walk you through a day on the job.
Core Content
This idea walks around your house all day. Knowing one thing well often unlocks several others. That is true of tools, of Scripture, and of numbers. This is worth learning because your addition facts are already doing double duty. 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.
This idea is simple once you see it. If you know 7 plus 5 is 12, then you already know 12 minus 5 is 7 and 12 minus 7 is 5. You do not need to work them out. The same three numbers are just standing in a different order.
Whenever a subtraction problem stumps you, hunt for the addition fact hiding inside it. Ask which two numbers make this whole, and the answer will usually arrive quickly.
Watch out for this. The whole is always the largest of the three numbers, and it must be the one you start from when subtracting. If you try to subtract the whole from a part, the sentence will not be true and the story will not make sense. Try a few on your own, and be patient with yourself.
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