oct 4th: test #1 Flashcards
what is multiplication?
fast adding.
how to multiply decimals?
deal with decimals, count the number of digits after the decimal and then move decimal in answer same number of times.
divisibility rule for 2?
if the last digit is even.
divisibility rule for 3?
if the sum of the # is divisible by 3.
divisibility rule for 4?
if the last two # are divisible by 4.
divisibility rule for 5?
if the last # are divisible by 5.
divisibility rule for 6?
if the # meets the rule for 2 + 3 eg. 74, 484, 2688.
divisibility rule for 9?
if the sum of the # are divisible by 9.
divisibility rule for 8?
if the last 3 # are divisible by 8.
divisibility rule for 10?
if the # ends in 0.
divisibility rule for 11?
if the sum of every other digit = the sum of the remaining number
eg. 3856
divisibility rule for 12?
if the # follows the rules for 3 + 4. eg. 216
divisibility rule for 25?
if the last two digits are either 00, 25, 50, or, 75.
prime number:
only has 1 set of factors, can only be divided by 1 and itself.
composite number:
has more than 1 set of factors, can be divided by at least three numbers
example of prime numbers:
2, 3, 5, 7, 11, 13, 17, 19, 23, and 29.
what makes up a power?
a base and an exponent.
what is a power?
a numerical expression that shows repeated multiplication.
what does the base do (power)?
the number being multiplied.
what does the exponent do (power)?
the amount of times to multiply the base.
how to multiply powers?
if the base is the same then add the exponents
eg = 4 to the power of 3 + 4 to the 5 = 4 to the power of 8.
how to multiply powers when the base and exponents aren’t the same?
if the bases are different you must solve/calculate differently.
how to divide powers?
if the bases are the same then subtract exponents.
eg. 7 to the power of 7 divided by 7 to the power of 4 = 7 to the power of 3.
how to divide powers with brackets?
when dealing with brackets, you multiply the 2 exponents together.
how to multiply powers when bases are different but exponents are the same?
multiply bases and leave the exponents.
what is expanded form?
showing a number while separating each ones, tens, hundreds, thousands…
342 = expanded form - 300 + 40 + 2.
what is scientific notation?
easy to express either really large or really small numbers.
342 = scientific notation - 3.42 x 10 to the power of 2.
what are the 3 steps of scientific notation?
- decimal always goes between first and second digit.
- mental multiply by base 10 to move decimal. This number becomes exponent over ten.
- Rewrite using base 10 with exponent.
for scientific notation: if we move the decimal ____ than we have a positive exponent
left.
for scientific notation: if we move the decimal RIGHT than we have a ____ exponent.
negative.
what is multiplying by power of 10?
when multiplying by power of ten, the decimal moves 1 spot for every power (exponent)
how to multiply by base 10 with a decimal?
the decimal moves 1 spot to the left for every power of 10.
eg. 327 x 0.01 = 3.27
what is dividing by power of 10?
when we divide by a whole number the answer becomes smaller which means the decimal is moving left 1 spot for every power of ten. which also happens to each exponent.
what is dividing by power of ten with a decimal?
when we divided by a decimal power of ten the answer becomes larger when we move the decimal to the right.
if you are expressing dividing by powers of 10 with a house…
NO DECIMAL IN HOUSE!!!
i hate
lazy people
NEVER BACK DOWN NEVER WHAT??
NEVER GIVE UP
