Two of the most common things to do with money are to add and subtract it. You would add money to figure out your total bill at a store, how much you owe someone, or how much money you have in total. You would subtract money to figure out how much change you’ll get back, how much someone owes you, or how much money you have left after you’ve been shopping. Being able to add and subtract money is very important.
First, we’re going to practice adding money. Adding money is very similar to adding whole numbers together, there is just one very important part that you need to keep in mind. When adding money, you need to add the cents together first, then add the dollars. When you report your answer, you will report both the dollars and the cents. Let’s practice this a bit.
At the grocery store, you want to get two things. You want a gallon of milk, which costs $2.79. You also want a loaf of bread, which costs $1.99. What will your total be? In order to do this, you need to add the two numbers together. The problem would look like this:
You would go ahead and add the numbers together as normal, starting in the column all the way to the right and working your way towards the left. Don’t forget to carry numbers when you have to. The addition looks like this:
The most important parts to remember here are to line up your decimals, and to put the dollar sign ($) in front of your answer. Without the dollar sign, your answer will be marked incorrect.
Let’s try another addition problem. This time, it will be more complex. At the grocery store, you want to buy a can of soup for $1.39, a head of lettuce for $1.69, a gallon of orange juice for $2.99, a package of chicken for $5.95, and a frozen pizza for $7.89. What will your total be? Here’s what the set up of the problem looks like:
Now, just add the amounts together (from right to left) carrying numbers when necessary, like this:
Thus, your final answer is $19.91. Don’t forget the dollar sign and decimal point! Those are two of the most important things in making sure you have the correct answer.
Subtracting money is very similar to adding money; in fact, you’ll set up the problem the same way, except you will be subtracting instead of adding. When you subtract money, you subtract the cents first, and then the dollars (you’re moving from right to left, just like when we added). Sometimes, you’ll be required to borrow in order to complete the subtraction problem.
Here’s an example problem: At the store, you spend $18.95 on a new pair of jeans. If you pay the cashier with a $20 bill, how much change will you get back? The problem would look like this (make sure decimal points are lined up!):
And here’s what the subtraction (with borrowing) would look like:
Let’s try one more example problem of subtracting money. George spends $15.62 at the grocery store and $19.48 at the electronics store. He had $50 before he started shopping. How much did he have left over when he got home (assuming he didn’t buy anything else)?
This is a two step problem. First, you have to add the two amounts that he spent together. Then, you take that amount and subtract it from what he had to start with. First, we’ll show the addition:
Now, we’re going to take the answer from the addition and subtract it from $50, like this:
Therefore, George would come home with $14.90 after his day of shopping.