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Write and Solve Expressions. Mrs. Carter 4 th Grade. Can you evaluate 12 – (3+2) ? What does the word evaluate mean? Let’s review Order of Operations! Stand up and sing!. Now solve the expression with your neighbor. 12-(3+2) Raise your hand to give the answer.
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Write and Solve Expressions Mrs. Carter 4th Grade
Can you evaluate 12 – (3+2) ? What does the word evaluate mean? Let’s review Order of Operations! Stand up and sing!
Now solve the expression with your neighbor. 12-(3+2) Raise your hand to give the answer. You have all seen the gray box symbol in math problems. What would happen if I took the 3 out and instead put in a gray box? 12 – ( +2)
Let’s Write Expressions! Lia has 3 baseball cards. Her friend gave her some more. How many cards does Lia have? 1st- Write the # of cards Lia has:3 2nd- How many cards did her friend give her? You don’t know so what do we use in its place? That’s right a variable!
If Lia’s friend gives her 5 more cards, how many will she have? You need to find the value of 3 + n when n=5 1st write the expression. 3 + n 2ndReplace the n with 5. 3+5 3rd-Add 3 +5, So the value of 3+n when n=5 is 8.
Latisha made 3 fewer baskets than Felicia. Write an expression for the number of baskets Latisha made. 1st Write the expression in words. Latisha’s baskets= 3 fewer than Felicia 2nd Let a variable represent the baskets Felicia made. Let’s use k. 3rd Write the expression: K – 3 Felicia’s Baskets – 3= Latisha’s baskets
Mrs. Carter and some of her homeroom kids eat apples at lunch. Today, 3 of her kids are eating apples. What is the value of 1 + c when c=3? How did I get the expression 1 + c ? What is the value of the expression? That’s Right! 4!
Write Expressions Hint: All of these expressions mean 2 times y: 2 x y, 2y, 2· y Let the variable Y stand for the number of cubs the ranger saw last week. • Twice the number of cubs seen last week 2y • 2 less than the number seen last week y-2 • Half the number seen last week y ÷ 2 • 2 more than the number seen last week y + 2
Write Expressions (Cont.) Let the variable Y stand for the number of cubs the ranger saw last week. • 5 fewer cubs than seen last week y - 5 • Four times the number seen last week 4 x y or 4·y or 4y
Solve Expressions What is another way to say solve? Evaluate or simplify Evaluate 2n when n=3 1st Write the expression 2n 2nd Replace n with 3 2 x 3 3rd Simplify the expression 2 x 3= 6
Guided Practice:Get out your whiteboards and work with me! Find the value of the expression when n=6 1. 2 x n + 5 2. 4n ÷ 4 Write an expression for each situation. 4. Danielle ran 6 fewer miles than Martha last week. Write an expression for the number of miles Danielle ran. 5. Paula had c baseball cards. She separates them into 3 equal groups. Write an expression to show the number of cards in each group.
Talk Math • Apply what you have learned about writing expressions to describe a situation that could be represented by: x-6
White board Practice MB pg. 137 #s 2,3,5,6
Independent Practice • MB pg. 138 #s 9-35 odd
Closure • What did we learn today? • Now what? How can this help us in life or in future lessons?
Exit Ticket Write an expression for the situation. • There are 3 more bear dens this year than last year. How many bear dens are there this year? • Describe a situation that could be represented by 12 – a. 3. Evaluate (n-5) +23 if n=10