MISSING NUMBER IN EQUATION

MISSING NUMBER IN EQUATION

By Elsa Yusoff

Multiple Choice

Which number will make this number sentence true?
8 + ___ = 10

• 18
• 2
• 6
• 1

Missing Variables in Equations

Missing Number Problems

Multiple Choice

Joy had 12 pencils in all. She had 5 pencils in her pencil pouch and some in her desk. How many pencils did she have in her desk? (Hint: 5 + ____ = 12)

• 7
• 17
• 3
• 1

Let's look at this story problem:

Natalie picked 38 strawberries on Monday. She picked some more on Tuesday and had a total of 60 strawberries. How many strawberries did she pick on Tuesday?

Solving mising number addition problems

• To find a missing addend, we have to subtract

• Example: to find 7 + _ = 10, we would flip the problem and subtract: 10 - 7 = ?

• Our answer is the missing number

Multiple Choice

Which number will make this number sentence true?
2 +6 = ___ + 3 (Hint: Start on the side with all of its parts.)

• 8
• 4
• 5
• 1

Natalie picked 38 strawberries on Monday. She picked some more on Tuesday and had a total of 60 strawberries. How many strawberries did she pick on Tuesday?

• Write an equation to show how to find the number of strawberries, s, Natalie picked on Tuesday.

• Solve the equation to find the number of strawberries Natalie found on Tuesday.

Multiple Choice

Isaac wanted to bring cupcakes for a class party. There are 21 students in his class. He already bought 6 cupcakes. How many more cupcakes does he need? (Hint: 6 + ___ = 21)

• 3
• 1
• 15
• 27

Let's try another one. This time, try writing the equation by yourself!

Multiple Choice

Which equation is true?

• 5 = 3 + 1
• 4 + 5 = 6 + 3
• 21 = 12
• 5 - 3 = 1

Subtraction: Missing Second Number

• The first number in a subtraction problem is called the subtrahend

• If it is missing, we subtract the difference to solve

• Example: 14 - _ = 6: to solve we subtract the difference 14 - 6 = ?

• The answer is our missing number

Seth gathered 83 blueberries to use for baking! He used some to make blueberry muffins and had 17 leftover. How many blueberries did he use to make blueberry muffins?

• Write an equation to show how to find the number of blueberries, b, Seth used to make muffins.

• Solve the equation to find the number of blueberries Seth used to make muffins.

Multiple Choice

The Packers scored 7 points and the Falcons scored 3 points. How many more points did the Packers score than the Falcons?

• 10
• 4
• 1
• 37

Multiple Select

Mrs. Reyes has 26 students in her class. If there are 14 girls in her class, how many boys are there?

Choose the TWO equations you could use to find the number of boys, b, in her class.

• 26 - 14 = b

• 26 + 14 = b

• 14 - b = 26

• 14 + b = 26

Multiple Choice

Brooklynn had 4 red fish, 2 blue fish, 5 yellow fish, and 1 dog. How many fish does Brooklynn have?

• 4 + 2 = 6
• 4 + 2 + 5 = 10
• 4 + 2 + 5 + 1 = 12
• 4 + 2 + 5 = 11

Multiple Choice

There are 7 boxes of pencils in the drawer. Each box has 12 pencils in it. How many pencils are there altogether?

Choose the equation that correctly shows how to find the total number of pencils, p.

• 7 + 12 = p

• 7 + p = 12

• 7 x 12 = p

• 7 x p = 12

Subtraction: Missing First Number

• The second number in a subtraction problem is called the minuend

• To solve, we must add

• Example: _ - 6 = 3: to solve we add: 6+3 = ?

• The answer is our missing number

Multiple Choice

Which equation is true?

• 1 = 11
• 11 - 3 = 4 + 4
• 5 + 5 = 5
• 1 - 2 = 3

Multiple Choice

A baker has containers to hold flour. Each container holds 5 cups of flour. She has a total of 45 cups of flour. Write an equation to find the number of containers, c, the baker has.

**Write the equation on your white board.

• 45 + 5 = c

• 5 x c = 45

• c - 5 = 45

• 45 - c = 5

Multiple Choice

The teacher gave each student a cookie. There are 5 boys and 10 girls. How many cookies did the teacher pass out?

• 5
• 10 
• 15
• 20

Multiple Choice

Which number will make this equation true?
1 + 1 = ___

• 0
• 2

Open Ended

There are 8 teams at a softball tournament. Each team gets an equal number of water bottles. There are 96 water bottles to be split evenly among the teams. Write an equation to find the number of water bottles each team gets. Use w to represent the number of water bottles.

*Write the equation on your white board.