1.03 Operations with decimals
Evaluate:
Evaluate:
Evaluate:
Evaluate:
Consider the expression: 9 + \left( - 2.4 \right).
Evaluate 9 + \left( - 2.4 \right).
Determine whether the following situations could be calculated using 9 + \left( - 2.4 \right):
Rose has \$9 in her account. If she spends \$2.40, how much does Rose have left in her account?
Lily has \$9 in her account. If she spends \$2.40, how overdrawn is Lily?
Ben has \$9 in his account. If he deposits \$2.40 into his account, how much does Ben have?
Consider the expression: 3.87 - \left( - 0.55 \right).
Evaluate 3.87 - \left( - 0.55 \right).
Determine whether the following situations could be calculated using 3.87 - \left( - 0.55 \right):
The temperature at midnight was - 0.55\degree \text{C}. By midday, the temperature was 3.87\degree \text{C}. What was the temperature change?
At midday, the temperature was 3.87\degree \text{C}. The temperature then fell by - 0.55\degree \text{C}. What was the final temperature?
It was really cold at midnight. During the morning, the temperature rose 3.87\degree \text{C}. By midday, it had reached - 0.55\degree \text{C}. What was the temperature at midnight?
Brad is currently \$18 overdrawn in his account. He knows that he needs to pay a \$61.61 bill from this account tomorrow. How much does he need to add to this account so he can pay his bill tomorrow?
Sebastian owes \$47.59 to each of his 3 friends. How much money does he owe altogether?
Jenny takes out a loan of \$2200. She pays back \$42.60 each month and doesn't have to pay interest. If she has made 5 repayments so far, how much does Jenny still owe?
Consider the following table that shows the temperature in different locations:
Find the change in temperature from London to Alaska.
If the temperature change from one of these locations to another was 16.7\degree \text{F}, what was the journey?
Cairo is 73.5\degree \text{F} warmer than Alaska. Find the temperature in Cairo.
| London | 53.8\degree \text{F} |
|---|---|
| Alaska | -4.5\degree \text{F} |
| Dudinka | -21.2\degree \text{F} |
| Vancouver | 13.1\degree \text{F} |
Cherry owes \$98.96 in total to 4 friends.
Assuming she owes the same amount to each friend, how much does she owe each one of them?
Cherry pays just 3 of her friends back. How much money did she pay back?
At midnight, the temperature in Buffalo is 45.7\degree \text{F}. Each hour the temperature decreases by 2.87\degree \text{F}. What is the temperature 5 hours later?
A diver is 3.5 \text{ m} below the surface of the water. He descends 1.47 \text{ m/s} for 3 seconds, then rises 0.46 \text{ m/s} for 6 seconds. The level at the surface is 0 meters, and 1 meter below is represented by - 1 meter.
Find the depth of the diver after 9 seconds.
The diver sees a turtle near the surface and needs to get to a depth of 0.35 \text{ m} below the surface within 4 seconds to snap the perfect shot. How many meters does he need to rise each second, assuming he will rise at a constant speed?
In direct sunlight, solar panels on a house generate 8.71 \text{ kWh} of electricity each hour, and on average, the house gets 7 hours of sunlight a day. Any unused power is returned to the main grid and the homeowner receives 33 cents per \text{kWh}.
Over a 24-hour period, the household's usage averages out to 1.87 \text{ kWh} each hour. How much will the homeowner expect to make each day by selling back electricity if they install the solar panels?