Problem: Article: A factorial, denoted by a whole number with an exclamation point, is the product of a series of sequential whole numbers. For example, 6!{\displaystyle 6!} is a factorial. The formula is n!=n(n1)(n2)321{\displaystyle n!=n(n-1)(n-2)\cdot \cdot \cdot 3\cdot 2\cdot 1}. This means that you extend the sequence of numbers until you get to 1. For example, 6!=6(61)(62)(63)(64)(65)=6(5)(4)(3)(2)(1){\displaystyle 6!=6(6-1)(6-2)(6-3)(6-4)(6-5)=6(5)(4)(3)(2)(1)} To calculate a factorial, begin with the denoted number, and multiply it by each sequential whole number, down to 1. A quick way to calculate a factorial is to use the x!{\displaystyle x!} key on a scientific calculator. First hit the number, then hit the x!{\displaystyle x!} key to see the product. For example, 6!=654321=720{\displaystyle 6!=6 imes 5 imes 4 imes 3 imes 2 imes 1=720}.
Summary: Identify a factorial. Evaluate a factorial using a formula. Calculate a factorial.

INPUT ARTICLE: Article: Glycerin is a moisturizer that will loosen the ink stain. Dip your swab into the bottle of glycerin, then gently but firmly blot the affected area until it's completely saturated. You can buy glycerin from a drugstore or an online retailer. Replace the swab with a fresh one if it becomes covered in ink. To protect other layers of clothing, like the back of a shirt, from any ink or glycerin that seeps through, place an old towel directly underneath the stain. This dilutes the detergent and thins it out so the stain can soak it up more easily. Stir the detergent and water together with a spoon until they're thoroughly combined. You can also do this in a spray bottle. Shake it vigorously to blend the 2 liquids. Choose a gentle detergent, particularly if you have delicate fabric. Look for a detergent that's marked "for delicates" or "for sensitive skin," for example. Just like you did with the glycerin, dab the area with the swab dipped in the liquid. Continue blotting until you've completely covered the stain. This allows the glycerin and detergent mixture to work on the stain. Set the clothing somewhere where it won't be disturbed, like on top of the washing machine or draped over a drying rack. Monitor the time with the clock app on your phone or a kitchen timer. Check the label on the item of clothing to see if there are any special directions for how to launder it. For example, if you're dealing with delicates, like a silk blouse or rayon skirt, you may need to wash them by hand or let them air dry. After washing your clothing, examine it to be sure that there is no trace of the stain left before you dry it. If there is still some ink, repeat the process as many times as necessary to remove it.

SUMMARY: Dab glycerin on the ink stain with a cotton swab. Mix 1 part laundry detergent with 1 part water in a small bowl. Use a cotton swab to apply the detergent and water mixture to the stain. Let the clothing sit for 10 minutes. Wash the clothes as normal, following the care instructions.

In one sentence, describe what the following article is about: You don't want your lighter to touch the candle at all. However, it works best if you can move your flame within the column of smoke from your candle. Light the candle smoke as soon after you blow out the candle as you can. You can light any area around the candle that you see smoke, even if it isn't directly above the wick. To make your trick more impressive, try relighting the smoke of the candle from different distances above the candle. This will help you understand how far away from the candle you can still light it. Begin at about an inch above the candle. Then, move farther upward, in small increments, until the candle no longer lights. If you want to present this experiment, as a magic trick, you want to provide a bit of a show to the audience of your friends and family. Talk through the trick. Try to catch their eyes. You want them to only focus on the candles when you're about the relight them without touching the wick. Talk in a booming voice, and project your confidence.
Summary: Light a match or lighter about an inch above the candlewick. Experiment with heights. Add a flourish.

In one sentence, describe what the following article is about: If you're using a traditional fixed phone or landline, pick up the receiver and listen for the dial tone. There must be a dial tone before you can make a call. To make a call from a mobile phone, turn on your phone, go into the telephone application, and bring up the keypad so you can dial the number. Every country has an international call prefix, also called an exit code, that must be dialled before you can call out of the country to another one. Dial 00. This is the international call prefix for Portugal, and it must be dialled before making calls abroad. If you're calling from a mobile phone, there may be a shortcut for the international call prefix. Look for the + sign, which is the shortcut. Sometimes it's the same as the 0 button, and sometimes you can use ** as a shortcut. Just like every country has a unique international call prefix to dial out, so too does every country have its own code that you dial when you want to call in. Dial 1. This is the country code for the US. It's also the country code for Canada and the Caribbean, because like international call prefixes, country codes can be shared by multiple nations. A country code can be one, two, or three digits long, and some countries have separate codes for mobile phones and landlines. The US, however, is not one of these countries, so the code will always be the same, regardless of what kind of phone you're calling. Bigger countries have area or city codes that divide larger geographical areas into small sections, and countries like the US have hundreds of area codes. Most states have multiple area codes, and you will need to know the particular area code for the state and region you're calling. Area codes in different countries can be one, two, or three digits long, but in the US they are all three digits. When calling smaller countries, they may not actually have area codes, in which case you would only dial the international call prefix, followed by the country code and local number. This is the specific and direct number of the person or organization you wish to call. This could be a landline on a fixed phone or a mobile number. In the US, local numbers are seven digits long. Once you've inputted all the numbers, the number you dial should look something like this: 00 1 123 456 7890. In this example, 00 is the exit number for Portugal, 1 is the country code for the US, 123 is the area code, and 456-7890 is the seven-digit local number. If you're calling from a fixed phone, it will automatically begin to dial when you've inputted all the right numbers. However, on a mobile phone, you will have to press Send, Talk, or the telephone icon to actually prompt the phone to dial the number you've inputted.
Summary:
Pick up the receiver. Dial the international call prefix. Dial the country code. Dial the area code. Dial the local number. Press Talk on a mobile phone.