MCAT math shortcuts
sin90
1
when the number is the same above and below the divisor it is
1
80/20
cancel the 0's and the answer is 4
cos is
x on the graph
The square root of x is the same as
x^1/2
Ka
x^2/initial molarity
sin is
y on the graph
To find SOHCAHTOA
you look at the angle and its relation to theta
To multiple exponents in scientific notation, you add them
(2x10^4)(4x10^2)-> 8x10^6
cos180
-1
log8 times any number will give .1
-1og8x10^-3-> .1
log3 times any number will give .5
-log3x10^-3--> 2.53
log5 times any number will give .3
-log5x10^-3--> 2.3
cos90
0
sin0
0
sin180
0
1/10
0.1
1/9
0.111
1/8
0.125
1/7
0.143
1/6
0.16
to divide fractions, you multiply by the reciprocal
1/3 / 1/2-> 1/3 x 2/1
How many kilograms are in a gram?
1000 (10kg=10000g)
How many miligrams in a gram?
1000 (10mg=0.01g)
To multiply numbers by 10, you add a 0 or move the decimal place
2.3 x 10 =23 or 23 x 10= 230
To divide numbers by 10 you remove a 0 or move the decimal place to the left
30 /10= 3 or 0.53/1000= 0.00053
To divide exponents in scientific notation, you subtract
3x10^6/6x10^3-> 1/2 x10^3-> 0.5 x10^3-> 5 x10^2
when adding in scientific notation with the same exponent, it does not change
4.7 x 10^-3 + 2.3 x 10^-3 = 7.0 x 10 ^-3
if you want to make the exponent the same, you divide it by 10
5 x 10 ^3/10 -> 50x10^-4
Square is when a number is multiplied by itself
5^2= 25
scientific notation is a shorthand for writing very large or very small numbers
6300-> 6.3 x10^3 or 0.0045-> 4.5 x10^-3
to find the log of a number just look at the 0's
log of 100--> 2
to find the negative log of a number, just look at the exponent
log1x10^-10--> -10
percent
part/whole
SOHCAHTOA
sin=opp/hyp cos=adj/hyp tan=opp/adj
To find square root of scientific notation, you take the square root of the whole number and square root of the power (divide it by 2)
√1x10^-6 -> 1x10^-3
1/5
0.2
1/4
0.25
1/3
0.333
1/2
0.5
cos60
0.5
sin30
0.5
cos45
0.7
sin45
0.7
1/12
0.83
1/11
0.9
cos30
0.9
sin60
0.9
cos0
1
to multiply difficult or complex fraction make the bottom number 100
7/33 x 3/3-> 21/100-> 21%
