How do you know if a number is significant? In this video I'm going to explain the 6 significant figure rules.
But don't worry, you don't have to memorize them all. Alright let's do this!
Hello hello Melissa Maribel here, and I help students like you understand what you just learned class, so you stress less
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So what are significant figures?
significant figures or
sig figs are the digits within a number that help determine how accurate a data value or measurement is and
Of course there are rules! Rule number 1, All numbers that are not zero are significant.
Looking at this first example every single one of these digits is significant because they are non-zero
numbers. Rule number 2
Any zeros that are in the middle of
non-zero numbers are
significant. These two zeros are in the middle of five and eight, five and eight are two non-zero numbers, so every single digit counts as
significant. Rule number 3, zeros after the decimal are
significant. These three zeros are after that decimal place, so every single one of these digits is
significant. Rule number 4, any
zeros and coefficients in scientific notation are
significant. Notice we have our scientific notation with something being multiplied by 10 to some sort of power, this 8 and this 0 are
significant.
Ok
Grab a pen write this down!
Do you need a pen? Ok you can borrow mine.
Alright now that you're ready write this down. Rule number 5, any leading or beginning zeros are NOT I repeat NOT
significant. Looking here these three are leading or beginning zeros
They do not count as significant only this four counts.
So there's only one sig fig. Rule number 6,
Any zeros in a large number without a decimal are not significant
these three zeros are
within a large number without a decimal so they do not count as significant, only the four does, there's only one sig fig.
But wait, there's more!
When adding and subtracting numbers, you look for the least amount of decimal places.
For this first example, your first step is to line up all the decimal places
Notice how 5004 there is no decimal however, where the decimal would be, would be after this four in the ones place
so
since we're looking for the least amount of decimal places that 5004 doesn't have a decimal place
So we will round to the ones place
Remember when rounding to the ones place or rounding any number
You look at the one right next to it, to the right
And if it is five or more you round up
Your final answer will be rounded up to 5488
We have four sig figs
Moving on to multiplication and division, when multiplying and dividing you look for the least amount of sig figs
Your first step is to figure out how many sig figs there are within each number
Notice that there are three sig figs in this first number and six sig figs in the second
So we will round to three sig figs
after multiplying
You then want to go ahead and stop at this zero.
So you remove that decimal place and there really only are three sig figs
Because of that last rule, this zero does not count. There is no decimal place, it's within a large number only these three
count as sig figs
It's time to check yourself. Go ahead and try these practice problems.
[Music playing]
Alright, let's recap what we just learned. Significant figures are the digits within a number that help determine
accuracy. The two rules that you got to know, any leading or beginning zeros do not count as significant. Any
zeros in a large number without a decimal are not
significant. When adding and subtracting numbers you look for the least amount of decimal places.
When multiplying and dividing, you look for the least amount of sig figs. If you feel like you need some more practice
Check the description box, below there's a link with practice problems and step-by-step
answers
And make sure you like this video if you learned something and subscribe if you want to see more videos just like this one.
Remember guys
I am here to show you how to pass Chemistry.
So leave a comment below letting me know what you need help with and I'll see you next time.
Has does not [laughs] sorry
[Hair Flip]
Melissa Maribel: How do you know if a number is...Camera man: No your hair
Melissa Maribel: I didn't touch anything
I don't know what's in my throat.
Thank you random hand.