2.2/2.3 Add and Sub of Rational Numbers Real Life Problems

​Copyright and Licensing Information for Open Up Resources 6–8 Math

​Without computing:

Discuss with you table group.​

Multiple Select

Which of the following are solutions to?

$$-2.7+x=-3.5$$  

• $$-3.5+2.7$$  

• $$3.5-2.7$$  

• $$-3.5-(-2.7)$$  

• $$-3.5-2.7$$  

A store tracks the number of cell phones it has in stock and how many phones it sells. The table shows the inventory for one phone model at the beginning of each day last week. The inventory changes when they sell phones or get shipments of phones into the store.

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​What do you know? What do you wonder?

​Cell Phones!

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A store tracks the number of cell phones it has in stock and how many phones it sells. The table shows the inventory for one phone model at the beginning of each day last week. The inventory changes when they sell phones or get shipments of phones into the store.

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​What do you think it means when the change is positive? Negative?

​Cell Phones!

​

A store tracks the number of cell phones it has in stock and how many phones it sells. The table shows the inventory for one phone model at the beginning of each day last week. The inventory changes when they sell phones or get shipments of phones into the store.

​

​What do you think it means when the inventory is positive? Negative?

​Cell Phones!

​

A store tracks the number of cell phones it has in stock and how many phones it sells. The table shows the inventory for one phone model at the beginning of each day last week. The inventory changes when they sell phones or get shipments of phones into the store.

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​Based on the information in the table, what do you think the inventory will be at on Saturday morning? Explain your reasoning.

​Cell Phones!

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Open Ended

What is the difference between the greatest inventory and the least inventory?

​Han's family got a solar panel. Each month they get a credit to their account for the electricity that is generated by the solar panel. The credit they receive varies based on how sunny it is.

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​Electricity Bill

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​ January they used $83.56 worth of electricity and generated $6.75 worth of electricity. Here is their electricity bill from January.

Current charges: $83.56

Solar Credit: -$6.75

Amount due: $76.81

​What do you notice? What do you wonder?

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How you can interpret the table to determine the amount due for the month.​

​Think, Pair, Share

​Electricity Bill

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Open Ended

What is the difference between the value of the electricity generated in week 1 and week 2? Between week 2 and week 3?

Label your answers.

Open Ended

The table shows the value of the electricity they used and the value of the electricity they generated each week for a month.

What amount is due for this month?

Multiple Choice

The temperature in a town is −4.7 ° C.

The temperature decreases 5.4°C.

What is the new temperature?

• 10.1°C

• −10.1°C

• 0.7

• -0.7