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Early math review
Counting American coins
Sal adds to find the total value when given an amount US coins.
Want to join the conversation?
- Why every student of Khan Academy have to learn US currency? What about other country's currency?(1 vote)
- Hi Amdadul
You don't have to learn about US currency unless you have a teacher who assigned the lesson.
Khan Academy started in the US, but the focus is on improving education worldwide. Currently, they're focusing on k-12 in India and the US, because those countries have school systems that are using KA the most. As more schools and countries use KA, they will likely expand the currency lessons.(6 votes)
- What is this?! These coins don't even have numbers on them. The sizes are weird. And some (like the "dime") don't even say the value with words.(0 votes)
- I know all of the coins look different just get used to them:
A penny is the only brown coin, and it is worth 1 cent.
A nickel is a medium-sized silver coin and is worth 5 cents.
A dime is the smallest silver coin and is worth 10 cents.
A quarter is a large silver coin and is worth 25 cents.
A half-dollar is the largest silver coin and is worth 50 cents.(9 votes)
- Why did the government start producing plastic bills instead of continuing to produce paper bills?(23 votes)
- Plastic money are harder to counterfeit than paper. Plastic money lasts 3-5 times longer than paper. Paper money shreds tiny bits and dust; causing problems for optical read sensors in ATMs/Vending machines. Plastic money will survive being washed in the laundry :)(34 votes)
- I am very disappointed to tell you that I do not understand American currency and finds it hard to add or take away currency of America as I live in England so can you put up questions on other currency as well?(14 votes)
- In American currency, 1 dollar ($1) is 100 cents. This means that 1 cent (1c) is 1/100 of a dollar.
Dollar bills (paper money) commonly have values $1, $5, $10, $20, $50, and $100. There are $2 bills, but they are rare.
The four common types of coins are pennies, nickels, dimes, and quarters. Less common types of coins are 50-cent pieces and dollar coins.
A penny is 1 cent.
A nickel is 5 cents.
A dime is 10 cents.
A quarter is 25 cents.
Have a blessed, wonderful day!(26 votes)
- How did money get its name?(5 votes)
- The word "money" is believed to originate from a temple of Juno, on Capitoline, one of Rome's seven hills. In the ancient world, Juno was often associated with money. The temple of Juno Moneta at Rome was the place where the mint of Ancient Rome was located.(12 votes)
- what was the first coin made(3 votes)
- THe first US-minted coin was the half-disme (pronounced deem), that was minted in 1792. Prior to this, there were many differing types of state currencies and the continental currency used in the revolutionary period, but as those began to become too confusing or devalue horrendously, the gvernment adopted the dollar system.(4 votes)
- why is been franklin on a 100 dollar bill if he's not a president all others are presidents(3 votes)
- A nickle represents 5 cents and a dime 10 cents. Why is the area of a nickle coin bigger than that of a dime? It's too ridiculous, isn't it?(2 votes)
- Hi bladedrinks !
At first, nickels and dimes were made of silver. In fact the nickel was not called a nickel back then, it was called a "half disme" (pronounced "half dime") because it was half the value of the dime and made of the same material. However, this meant that the half dime (now known as a nickel) was only half the size of the already small dime! People responded to the size of the half dime, saying that it was much too small to handle nicely, so the government changed the coin so that it was made out of nickel, which was a less valuable material. Because the half dime was now made out of nickel instead of silver, (nickel was less valuable than silver) the half dime ended up being bigger than the dime. Since the half dime was being made out of nickel, people started calling the five-cent coin a "nickel," which is how we refer to it today. Nickels are now made up of less valuable materials, but the size has remained the same because of tradition. Hope I helped.(6 votes)
- No dollar coins or half dollars?(3 votes)
- These coins are very rarely used in the US today. While these are still valid currency, they are not distributed in the quantity the other denominations are.(3 votes)
- Can you also do Indian coin's also?(3 votes)
- Khan Academy has a separate area for Indian math
https://www.khanacademy.org/math/in-math-by-grade(3 votes)
Video transcript
- Let's get some practice counting money! So I have six coins right over here, and these are all United States coins, we're counting money in the United States for these examples, and
what is this first coin? Well, this is called a
quarter, or a quarter-dollar, so it represents 25 cents,
and we could write it out as 25 cents, but I'll just
keep that one like that. Now this one's another quarter, so it is also going to be 25 cents. Now this one looks different, but it's just the other side of these coins. This is what the other side looks like. So this is also going to be 25 cents. These are three quarters right over here. So how much money do these
three quarters represent? Well, it's going to be
25 plus 25, which is 50, plus 25, which is going to be 75, so these three quarters
are going to be 75 cents. And remember, 100 cents make a dollar, so this is still less than one dollar. But we're not done yet. We have this nickel, this
is a nickel right over here, that represents five
cents, and then we have another nickel here, it looks
different, but it's just the other side, this is the head
side, this is the tail side. So this is also another five cents, and so these two nickels,
if you add them together, they are going to represent 10 cents, and then finally, you
have a penny, and a penny, and it even says it right over
here, is one cent, in fact, they all say it here, this is
five cents, this is one cent. So this right over
here's gonna be one cent. So what is 75 plus 10 plus 1? Well 75 plus 10 is 85, plus 1 is 86, so this is equal to 86 cents. And if it felt a little bit
too fast to count up 25, 50, 75 in your head, you could also add them up. 25, 25, 25, plus 5, another 5, plus 1. You could add them up this way, and then what would you get? 5 plus 5 is 10, plus 5 is 15,
plus 5 is 20, plus 5 is 25, plus 1 is 26, so that's
two tens and one six, put the two tens up here. 2 plus 2 is 4, 4 plus
2 is 6, 6 plus 2 is 8. So you could get 86 cents, either way. Let's do one that has
even more coins in it. So here we go, we have, so what
is it, what's going on here? This right over here is a quarter,
that's going to be 25 cents. 25 cents, and then, we
have one that we didn't see in the previous example,
we have two dimes. A dime represents 10 cents,
so we have two dimes, where we can have those
each represent 10 cents, then we have two nickels,
we've already seen those each represent
five cents, so 5 and 5, and then we have four pennies,
one, two, three, four. Now we could put each penny
separately, like that, or we could say, look, four
pennies, each of them represent one cent, so that's
going to be four cents. So let me do it that way. So, this one, two, three, four, that's going to be four cents. And then we could just add everything up, so 5 plus 0 plus 0 plus 5 is
10, plus 5 is 15, plus 4 is 19. 19 is one ten and nine ones, so I could put the one ten in the tens place, 1 plus 2 is 3, plus 1 is 4, plus 1 is 5. So it's five tens, five tens
and nine ones, so 59 cents. This right over here is 59 cents. And notice, we have more coins, but it represents less value
than the previous example. That's because we had a lot of coins that didn't represent a lot of values, like, we had these four pennies here, while the previous example,
we had three quarters! Each of these quarters is
equivalent to 25 pennies, so we're able to represent more money with fewer coins in the first example.