Lesson 1

From the Fish Hatchery

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes

This can be used as a Problem of the Week.

Responses will vary. Ask students to check their responses using a calculator.

Possible response for numbers 1–50:

Strategies will vary.

Possible response: I thought about how I could combine 5 and 2 to make as many numbers as possible. For example, I knew that 5 − 4 = 1, but since I did not have a 4 key I used 2 + 2 instead of 4. I also knew that I could combine 2 and 5 to make 2-digit numbers. When I got to 17 I used 22 − 5 and when I got to 50 I used 25 + 25.
Possible response:
55 + 22 + 2 + 2 + 2 = 83

Brandon and John found an old calculator. John tried the calculator and found that only the clear key and five other keys worked:

“I have an idea,” said John. “Let's see if we can use the keys that work to make all of the numbers from 1 to 50.”

Help John and Brandon. See if you can make all of the numbers from 1 to 50 on the calculator display using just these six keys. You may use each key more than once, or not at all. Make a list and explain what keystrokes you need to produce each number. Remember, you may use only the keys listed above—the others are broken.

Example: 50 = 55 − 5

When you have finished making your list, write a paragraph explaining all of the strategies that you used to find your solutions. Use the Math Practices page in the Student Guide Reference section to guide you.