Finding Fractions Around YouWe don't want you thinking that you will only use fractions in math classes. Fractions are around you every day of the week. Do you know about that container of milk in your refrigerator? It is probably a half gallon. Drinks you buy in the store might come in half-liter bottles. When you want to buy some food at the deli, you might ask for a quarter or half a pound. Your parents probably think about how much gas they have every day. It's great to have a full tank, but they also know if they have three quarters, a half, or a quarter of a tank left.
Those examples are easy to imagine, but what about adding fractions and multiplying fractions? In the fraction word problems section, we told you about pieces of pie at a party. If a pie has six pieces, you need to know if you have enough food for everyone. What about drinks? If you have a half gallon of water, will it be enough for everyone to get two glasses each? It's all about fractions.
ConstructionWe admit that the decimal system is easier for measurements, but the United States still uses inches and feet to make measurements. If you want to build a table, you might need to have it six feet two and a quarter inches long (6' 2 1/4"). Let's say you cut the board too long and your boss says, "Cut off a sixteenth of an inch." You need to know how long that is or everything gets messed up.
You could also have a day when you need to buy a piece of plywood. You might need five pieces that are thirteen and five eighths of an inch long. How much plywood would you need? You'll be multiplying fractions to get those numbers. (5 x 13 5/8 = ?)
CookingWe talked about measuring in construction. Cooking is the same. You need to measure things whenever you follow a recipe. You have half-cups, quarters of a teaspoon, and a whole bunch of other measurements. Your cookbook might only have recipes that serve two people. What if you have some friends over? What if you're a professional chef and you are making food for a party? You will need to do a bunch of multiplication so that your food comes out right. You'll also need to work with fractions to find out if you have enough food in the pantry or if you need to buy more.
Fractions and Ratios in ScienceThis won't be a surprise, but fractions and ratios are used in science. Luckily, most of science has moved to the decimal system when it comes to measuring amounts. You will still need fractions if you are counting things. Let's say you are working with colonies of bacteria. You will need to count the numbers of different bacteria in a dish. You could get 6 of one species, 3 of another species, and 4 of a third species. Where are the fractions? You actually have 6/13, 3/13, and 4/13 in that dish. Those values can tell you a lot about how bacteria reproduce and survive.
Don't Give UpWe just want you to know that your efforts to learn fractions are not a waste of time. Fractions are very important in the real world. You might meet adults that say they don't use fractions, but that is not true. They probably don't think about it because they are so used to them. While an adult might not remember how to divide fractions, we bet they can look at a cake and know whether they have enough for a party. They also know if they have enough gas to make it home if their car can go 26 1/2 miles for each gallon.
We'll leave you with one last problem...
You are driving along and see that your tank is only 3/8 full. The tank holds 14 gallons of gas. Your car goes 22 1/2 miles for every gallon of gas. How far can you drive before you run out of gas?
• How much gas do you have? 3/8 * 14 = ?
• Take the number of gallons and multiply it by 22 1/2 to get your answer.
We'll let you figure out all of the details. The answer is 118.125 miles (118 1/8 miles).
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- Mixed Numbers 2
- Subtraction 1
- Subtraction 2
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Useful Reference MaterialsWikipedia:
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