Unknown Addend in Addition Problems - first grade
This is a complete lesson with instruction and exercises for initial teaching on the UNKNOWN or MISSING ADDEND concept in first grade math. Children solve simple addition equations with single-digit numbers where one addend is missing or unknown.
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Something is missing from the
addition. How many are in the second group? That's what is missing! There should be a total of 5 dots. Draw 4 in the second die face. |
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There should be a total of 4 dots. The second die face has two.
Read: “2 plus what number makes 4?” |
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1. Draw more dots for the addition. Write the missing number. The total is on top.
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2. Draw more dots to show the missing number. Write the missing number.
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3. Draw more dots
in the empty box for the missing number. Read the problems aloud:
“2 plus how many makes 4?”
a. 2 + ______ = 4 |
b. 4 + ______ = 4 |
c. ______ + 3 = 4 |
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d. 2 + ______ = 5 |
e. ______ + 1 = 3 |
f. ______ + 4 = 5 |
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There are no dots in either die face. The first die face is missing the dots. The second die face is supposed to have none, since there is a zero below it. Draw 4 dots in the first die face, because 4 + 0 = 4 . |
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4. Draw dots
in the boxes for the missing numbers. Notice that some boxes are supposed
to have zero dots.
a. 0 + ______ = 4 |
b. 2 + ______ = 2 |
c. ______ + 0 = 3 |
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d. 3 + ______ = 3 |
e. ______ + 0 = 2 |
f. 0 + ______ = 1 |
5. Draw dots to illustrate each addition problem. Find what number is missing.
a. 4 + ______ = 5 |
b. 1 + ______ = 2 |
c. ______ + 3 = 5 |
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d. 3 + ______ = 4 |
e. 2 + ______ = 3 |
f. ______ + 2 = 4 |
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g. 1 + ______ = 5 |
h. ______ + 1 = 4 |
i. 3 + ______ = 3 |
6. Solve. Now,
the missing number goes inside the shape. You can draw dots to help you.
Remember, the number after the “ = ” sign is the total.
a. 2 +  = 5 |
b.
 + 2 = 4 |
c.
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d.
 + 3 = 3 |
e. 3 +
= 5 |
f. 0 + |
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g. 3 + |
h.
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i.
+ 1 = 5 |
7. Practice “normal” addition.
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a. 1 + 1 = ______ 2 + 1 = ______ |
b. 4 + 0 = ______ 3 + 1 = ______ |
c. 1 + 4 = ______ 2 + 2 = ______ |
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d. 2 + 3 = ______ 1 + 4 = ______ |
e. 0 + 5 = ______ 1 + 2 = ______ |
f. 3 + 2 = ______ 4 + 1 = ______ |
8. Find the missing number. The marbles illustrate the total. Notice the patterns!
a.
0 + ______ = 3 1 + ______ = 3 2 + ______ = 3 3 + ______ = 3
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b.
0 + ______ = 4 1 + ______ = 4 2 + ______ = 4 3 + ______ = 4 4 + ______ = 4
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c.
0 + ______ = 5 1 + ______ = 5 2 + ______ = 5 3 + ______ = 5 4 + ______ = 5 5
+ ______ = 5 |
This lesson is taken from Maria Miller's book Math Mammoth Addition 1, and posted at www.HomeschoolMath.net with permission from the author. Copyright © Maria Miller. The lesson addresses the following Common Core standard for 1st grade: 1.OA.8.
Math Mammoth Addition 1
A self-teaching worktext for 1st grade that covers addition concept, missing addend problems, and practice of addition facts within the context of fact families (providing structure for the facts learning).
Download ($3.95). Also available as a printed copy.
