Is the Cup Half-Empty or Half-Full?
Eh, it doesn’t matter. Whether you see it as half-empty or half-full, the cup has the same amount of liquid in it. Now, the exam might ask you how many ounces are in that cup that is half-filled. Perhaps, you might get asked how many gallons are needed to be able to fill a certain number of cups.
Addition
Stack your problem if it is already set up that way. Add your like units together, then determine if the smaller unit can be “upgraded”. If it can, move the appropriate amount to the larger unit.
For example, if you are adding 2 pints 8 ounces to 1 pint 10 ounces, you would first stack them, then add like terms together.
Don’t stop there. You have an “upgrade” opportunity. Look at the chart above. How many ounces are in one pint? That’s right, 16 ounces. In your answer, you have 18 ounces so move 16 of those ounces over to make another pint. That leaves you with 4 pints 2 ounces as the final answer.
Subtraction
To subtract, you will want to group like units the same as you do for addition. Unlike addition where you determine if an “upgrade” is needed, subtraction might need a “downgrade”. Let’s turn our addition example into subtraction.
You can’t subtract 10 ounces from 8 ounces without getting a negative number so how do you make it work? Try “downgrading” the 2 pints. Take one of those pints and turn it into ounces. Referring back to our chart, we know that would be 16 ounces.
Now you are ready to subtract!
Multiplication
Convert the problem to the smallest unit and multiply. The second step is to convert the answer to the units that the problem is requesting. Let’s start with something easy: Multiply 2 cups 10 ounces by 3.
First, you will convert the 2 cups 10 ounces to all ounces. Remember there are 8 ounces in each cup so 8 x 2 = 16 ounces. Add the 16 ounces to 10 ounces. Now your 2 cups 10 ounces is 26 ounces. Multiply 26 by 3 to get a total of 78 ounces.
We are not done yet! To finish, convert the 78 ounces to cups. To do this, divide 78 by 8. The final answer is 9 cups 6 ounces.
Ok, pop quiz! What if you were asked to multiply 2 cups 10 ounces by 3 cups 5 ounces? Stay calm and follow the steps like we just did. Convert them both to ounces.
We know 2 cups 10 ounces is 26 ounces from our last problem. Now, let’s convert 3 cups 5 ounces all into ounces. Since 8 ounces equals 1 cup, multiply 8 x 3 to get 24 ounces. Add 5 ounces. Now we have 3 cups 5 ounces equals 29 ounces. Multiply 26 by 29. Your total ounces is 754.
To convert 754 ounces back to cups, divide 754 by 8. The answer is 94 cups 2 ounces. This is an extreme example, bu if you are able to work through some hard ones now, working these problems when test time comes will be a breeze.
Division
Dividing measurement conversions has the same first step as multiplication: convert your measurement to the lower unit first. For example, if we needed to divide 4 quarts 1 pint by 3, we would convert the 4 quarts 1 pint all to pints. There are 2 pints in each quart so 2 x 4 equals 8 pints. Now add the one pint to make a total 9 pints.
Divide 9 pints by 3 to get 3 pints. Last, convert back to quarts. The final answer is 1 quart 1 pint.
