18/5 is basically 3 3/5 as a mixed number. When you convert a fraction to a decimal, you always want the denominator to either 10, 100, or 1000 so that the number is accurate. And so you multiply the denominator by what ever number will get 10, 100 or 1000, in which in this case is 10 when you multiply by 2. Multiply the numerator(3) by 2 so that it will be the same value. You should now have 3 6/10. After that, since 6/10 is basically 60/100, take out the 100 and move the decimal unit 2 units to the left of 60. And since you still have the whole number three, your final answer will be 3.6.
