To find the percentage, take the decimal and multiply it by 100. Another way is to move the decimal to the right two places.

\(\displaystyle 0.40*100=40\%\)

If something is reduced by two thirds, the new quantity is:

\(\displaystyle \frac{3}{3}-\frac{2}{3}=\frac{1}{3}\)

This can be represented as a decimal \(\displaystyle 0.\bar{3}\).

To transform 0.093 into a percent, move the decimal two digits to the right and then put in the '%' right after it.  In our case 0.093=9.3%

To calculate a percent from a decimal, multiply by 100.

\(\displaystyle 1.03\times 100=103\ percent\)

Write the statement as an equation and solve for \(\displaystyle x\):

\(\displaystyle 25=125x\)

\(\displaystyle \frac{25}{125}=\frac{125x}{125}\)

\(\displaystyle .2=x\)

Multiply the decimal by 100 to convert the answer to a percent:

\(\displaystyle .2\times 100=20\ percent\)

To convert a decimal to percentage simply move the decimal point to the right two decimal places.

Thus, \(\displaystyle 0\small \small .0078\) turns into \(\displaystyle 0.78\%\).

In addition to this simple trick, one could also convert a decimal to a percentage by reading the decimal aloud. \(\displaystyle 0.0078\) is read as "seventy-eight ten thousandths", this would look like \(\displaystyle \small \frac{78}{10,000}\). Since percentage is simply a representation of a part per hundred, if this fraction is reduced to a number over one hundred, we would get \(\displaystyle \small \frac{0.78}{100}\), thus 78%.

Given \(\displaystyle 0\small .048\), moving the decimal two places to the right result in \(\displaystyle \small 4.8\%\).

Also, this decimal number read aloud is "forty-eight thousandths" , which is \(\displaystyle \small \small \frac{48}{1000}\). Since percentages are representations of a part per hundred,when the fraction is simplified by dividing both the numerator and denomintaor by ten to reduce the fraction to be out of one hundred, the numerator is left at \(\displaystyle \small 4.8\), or \(\displaystyle \small 4.8\%\).

Given \(\displaystyle \small 43.009\), move the decimal point two places to the right, resulting in \(\displaystyle 4300.9\%\).

Also, \(\displaystyle \small 100\%\) is equivalent to \(\displaystyle \small 1.0\). Thus, \(\displaystyle \small 43.009\) is roughly that \(\displaystyle \small 1.0\), or \(\displaystyle \small 100\%\), multipled by about 43. So we can expect our answer to be way over \(\displaystyle \small 100\%\)!

\(\displaystyle 0\small .000070 + 0.000003 = 0.000073.\) To convert decimal to percentage, move the decimal to places to the right, resulting in \(\displaystyle 0\small .0073\%.\) 

\Alternatively, we could convert the decimals to percentages from the beginning.  \(\displaystyle 0\small .007\% + 0.0003\% = 0.0073\%\). 

\(\displaystyle 0\small .4397\) to a percentage is solved by moving the decimal point two places to the right, resulting in \(\displaystyle \small 43.97\%\).

This decimal read aloud reads "four thousand three hundred ninety seven ten thousandths", which in fraction form \(\displaystyle \small \frac{4397}{10,000}\), when reduced is \(\displaystyle \small \small \frac{43.97}{100}\), which is \(\displaystyle \small \small 43.97\%\).