Lesson Plan - Get It!
How many different things do you have to do before you go to bed? Change your clothes, brush your teeth, wash your face, maybe have a snack? Getting ready for bed is a multi-step problem! How does that work in math?
Many things in life require you to do more than one step, like preparing a meal, taking a bath, doing your homework, playing a game, or walking the dog!
The same is true in math. Many mathematical problems require you to take more than one step to solve. Multi-step problems are common in math, and you have already solved some of them! Multi-steps are used in problems like converting measurements, tracking time, and solving problems with parentheses. Most word problems in math are related to real-life situations! Learning about how to solve them can help you strengthen your problem-solving skills.
- In word problems, the first step is finding a number that is not in the story.
- Then, you use that number to help solve the second step of the problem.
- Identify the goal and the first step of the problem to get started.
Let’s look at this problem:
Sarah is 4 years older than Tina. Tina is 5 years older than Lisa. Lisa is 12 years old. How old is Sarah?
This is a two-step problem. We are asked to find Sarah’s age, but we only know Lisa’s age. So, we have to work backwards to find more information. This model can be used to help represent the information we know:
- Step 1: Finding a number that is not in the story. We need to know Tina’s age to find Sarah’s age.
- Step 2: Use the number from Step 1 to solve the problem. We can use Tina’s age to find Sarah’s age.
Let’s use a model to represent each girl.
Goal: Find Sarah’s age.
First step: Find Tina’s age.
- Lisa is 12. Label her rectangle.
- Tina is 5 years older than Lisa, so we can add another piece to her rectangle.
- Tina = Lisa + 5, so Tina is 12 + 5 = 17.
- Sarah is 4 years older than Tina, so we can add another piece to her rectangle to show it is more.
- Sarah = Tina + 4, so Sarah is 17 + 4 = 21.
- Lisa is 12 years old.
- Tina is 17 years old.
- Sarah is 21 years old.
Even though the problem only asked us to find how old Sarah was, we had to find Tina’s age first in order to find Sarah’s age.
Discuss with your parent or teacher:
- How do multi-step problems differ from other kinds of problems you have worked with?
- Is there a strategy you use when trying to decide which operation to use first?
- How would you explain to someone how the models can help you figure out a multi-step problem?
Don’t worry if you can’t draw the models perfectly. They are just meant to help you figure out what steps to take.
Let’s go to the Got It? section to practice making models and solving more problems!