Review: The Equal Sign, Fact Families, and Missing Numbers
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
You will meet this idea in ordinary days. Understanding structure beats memorizing lists. Structure keeps working when the numbers change. This is worth learning because these three ideas hold up everything you will do in second grade 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. Three big ideas from this strand belong together. The equal sign means both sides balance. A fact family is three numbers that build four sentences.
A missing number is just an unknown part of a fact family. Given 6, 9, and 15, you can write four sentences and fill any blank among them. Practice by covering one number in a family and finding it from the other two.
Try this connection. Given 6, 9, and 15, write all four sentences, then replace any one number with a blank and solve it. Fact families and missing numbers are the same idea wearing different clothes. If you get stuck, use your fingers or counters. Good mathematicians use tools.
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