MAFS.3.OA.4.8 SUPPLEMENTAL LESSON Writing equations for two-step word problems
Lesson Opening Ava bought a pack of 50 colored pencils. Her friend, Marisa, gave her 7 more pencils. Write an equation that represents how many pencils Ava has now. Use the letter p to represent how many pencils Ava now has.
Lesson Opening Ava bought a pack of 50 colored pencils. Her friend, Marisa, gave her 7 more pencils. Write an equation that represents how many pencils Ava has now. Use the letter p to represent how many pencils Ava now has. + = p
Lesson Opening Ava bought a pack of 50 colored pencils. Her friend, Marisa, gave her 7 more pencils. Write an equation that represents how many pencils Ava has now. Use the letter p to represent how many pencils Ava now has. + = p 50 7
Writing Equations for 2-Step Problems Step 1: Read the entire problem. Step 2: MODEL one sentence (or part) at a time. Step 3: Find the answer. Step 4: Write an expression for how you solved each part. Step 5: Use a letter for the unknown in the problem.
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together?
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 1: Read the entire problem.
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 2: Model the problem one sentence at a time. Pete
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 2: Model the problem one sentence at a time. Pete Sam
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 2: Model the problem one sentence at a time. Pete Sam
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 3: Find the answer. Pete Sam They have 15 books altogether.
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 4: Write an expression for how you solved each part. Pete Sam
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 4: Write an expression for how you solved each part. Pete Sam (2 x 5)
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? Step 5: Use a letter for the unknown in the equation. Pete Sam (2 x 5) = b Use a letter for the unknown
Writing Equations for 2-Step Problems Pete has 5 books. Sam has twice as many books as Pete. How many books do they have together? The reason there are parentheses around 2 x 5 is because you perform the operation in parentheses before you can add it to the (2 x 5) = b Use a letter for the unknown
LET’S TRY ANOTHER ONE…
Writing Equations for 2-Step Problems Step 1: Read the entire problem. Step 2: MODEL one sentence (or part) at a time. Step 3: Find the answer. Step 4: Write an expression for how you solved each part. Step 5: Use a letter for the unknown in the problem.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag?
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 1: Read the entire problem.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 3: Find the answer. There are 4 chocolates in each bag.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part.
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part. 18
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part. 18 – 6
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part. (18 – 6) ÷ 3
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part. (18 – 6) ÷ 3
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part. (18 – 6) ÷ 3
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 4: Write an expression for how you solved each part. (18 – 6) ÷ 3
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 5: Use a letter for the unknown in the problem. (18 – 6) ÷ 3 = c
Writing Equations for 2-Step Problems Tom has a box of 18 chocolates. He eats 6 of them and places the rest of them equally into three bags for his sisters. How many chocolates are in each bag? Step 5: Use a letter for the unknown in the problem. (18 – 6) ÷ 3 = c Use parentheses around what you have to do first.
ONE MORE...
Writing Equations for 2-Step Problems Step 1: Read the entire problem. Step 2: MODEL one sentence (or part) at a time. Step 3: Find the answer. Step 4: Write an expression for how you solved each part. Step 5: Use a letter for the unknown in the problem.
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box?
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 1: Read the entire problem.
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 2: Model the problem one sentence at a time.
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 2: Model the problem one sentence at a time. ?
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. ? Let’s work backwards. If I have 13 now and I just gave away 11, how many paperclips did I start with?
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. ? Let’s work backwards. If I have 13 now and I just gave away 11, how many paperclips did I start with? 13 11
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. ? Let’s work backwards. If I have 13 now and I just gave away 11, how many paperclips did I start with?
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. ? Let’s work backwards. If I have 13 now and I just gave away 11, how many paperclips did I start with? = 24
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. ? Let’s work backwards. 24 paperclips were in 4 boxes. So many were in 1 box? 24
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. 6 Let’s work backwards. 24 paperclips were in 4 boxes. So many were in 1 box? =
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 3: Find the answer. 6 There were 6 paperclips in each box. =
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 4: Write an expression for how you solved each part. Now, write the equation based on how you solved the problem.
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 4: Write an expression for how you solved each part
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 4: Write an expression for how you solved each part. ( ) ÷ 4
Writing Equations for 2-Step Problems Ms. Percy bought 4 boxes of paperclips. She gave 11 of the paperclips away to her students. Then she had 13 paperclips left. How many paperclips were in each box? Step 5: Use a letter for the unknown in the problem. ( ) ÷ 4 = p
Your Turn Step 1: Read the entire problem. Step 2: MODEL one sentence (or part) at a time. Step 3: Find the answer. Step 4: Write an expression for how you solved each part. Step 5: Use a letter for the unknown in the problem. Pedro has 24 toy cars in his bedroom. He has the cars equally divided into 3 boxes. If he gives 1 box away to his brother, how many toy cars does Pedro have left?
Your Turn Step 1: Read the entire problem. Step 2: MODEL one sentence (or part) at a time. Step 3: Find the answer. Step 4: Write an expression for how you solved each part. Step 5: Use a letter for the unknown in the problem. Ms. Bellas makes 32 cupcakes for her students. But before she could bring them to school her family ate 8 cupcakes. She packed the rest of the cupcakes equally into 3 containers. How many cupcakes are in each container?
Your Turn Step 1: Read the entire problem. Step 2: MODEL one sentence (or part) at a time. Step 3: Find the answer. Step 4: Write an expression for how you solved each part. Step 5: Use a letter for the unknown in the problem. At a restaurant each adult meal costs $12 and kids eat free. If a group of 14 people went to eat and 6 were kids, how much would it cost for the whole group to eat?
Your Turn Solve each problem. Match the problem to the equation that could be used to solve the problem.
Exit Ticket Write an equation with a letter representing the unknown for the following situation. Then solve for the letter. A painter needed to paint 26 rooms in a building. Each room takes 9 hours to paint. If she already painted 17 rooms, how many more hours will it take her to paint the rest?