# Multiplication and Division for Units of Ten

As you’re working through the physical sciences section of your MCAT you will be faced with unit conversions asking you to multiply or divide numbers by some factor of 10. This can occur in questions such as gram to kilogram or liter to milliliter conversions.

Given the time constraint on the MCAT and lack of calculator, you can’t afford to work out these examples the long and tedious way. Instead you want to use the factor of 10 trick which allows you to simply move the decimal (visible or imaginary) to quickly come up with a solution.

Watch the video below for a detailed explanation of this trick along with a few examples showing you how to work it out in record time.

## MCAT Style Questions Solved In This Video:

Unit Conversions Question 1: Convert 3.47 kilograms to grams.

Unit Conversions Question 2: Convert 0.53 grams into kilograms.

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This is video 2 in my series on MCAT Math Without A Calculator. Click HERE for the entire series

1. bianca says

How would i use this trick when multiplying 0.044 ×(2/3)? Im trying to solve a stoichiometric problem without a calculator.

• Leah4sci says

I doubt you are going to be asked this on the MCAT. Show me the question where this came up

2. Stacy says

How would the decimal trick work when dividing. For example 0.7/25 ?

• Leah4sci says

I’d simplify this one and combine with the other tricks.
0.7 x 10 is 7. We’ll divide the answer by 10
Round 25 down to 21 making the overall answer BIGGER
7/21 = 1/3 since both divide by 7.
1/3 = 0.3
now divide by 10 to complete the decimal trick for 0.03
The answer is GREATER since we rounded so..
<0.03 (calculator says 0.028 which is close enough)