math: decimals, percent  and fractions




Decimal numbers: are numbers that are written according to their place value. the decimal point is used to separate whole numbers from number values less than one



Fraction: is a numerical value that is not a whole number and a fraction is part of a whole.



Percent: is a number or an amount in each hundred


 A fraction, percent or decimal can change the form it is written as  but the value of the numbers don't change. Example: A half can be written as a fraction ¹/_{2 , as a decimal o.5 and as a percentage 50}%
if you want to  convert a decimal to a fraction, re-write using place value as denominator + simplify if possible. if you want to convert a decimal to a percent, multiply decimal by 100( move decimal 2 places right.) if you want to convert a fraction to a decimal, divide the numerator by the denominator. if you want to convert a fraction to a percent divide the numerator by the denominator + multiply by 100. if you want to convert a  percent to a decimal, divide by 100( move the decimal 2 places left.) if you want to convert a percent to a fraction, rewrite denominator of 100 + simplify, if possible.



when estimating percent you can easily use your benchmarks ( 50%, 25%,10%,5%, 1%0)
 50%:divide by2, 25%:divide by 4, 10%: move the decimal  1 place to the left. 5%: move 1 decimal place to the left then divide by 2 ,1%: move the decimal 2 places to the left. Example: 45% of 40, since 45 is not one of our benchmarks you can use 25%,10% and 10%. once you have did the math add the total amount of 25%,10% and 10% and you will get 18.

  By: Yoska Woldu