Writing Formulas and Substituting in a Formula - Revision Notes

[ 4 Votes ]

In addition to the revision notes for Writing Formulas and Substituting in a Formula on this page, you can also access the following Formulas learning resources for Writing Formulas and Substituting in a Formula

Formulas Learning Material
Tutorial IDTitleTutorialVideo
Tutorial
Revision
Notes
Revision
Questions
8.1Writing Formulas and Substituting in a Formula


In these revision notes for Writing Formulas and Substituting in a Formula, we cover the following key points:

  • What is a mathematical sentence?
  • What are mathematical operators?
  • Where does a mathematical sentence differ from a wordy sentence?
  • What are formulas? Why do we use them?
  • How to write a formula? What do we call its components?
  • What types of variables are there in a formula?
  • How to substitute the variables in a formula?
  • What is the procedure used when solving an exercise containing formulas?
  • How to convert wordy problems into formulas and vice-versa?
  • How to find the inverse formula when the original formula is known?

Writing Formulas and Substituting in a Formula Revision Notes

A mathematical sentence is a fact (it may be either true or false) that combines two expressions (written in mathematical symbols) connected through a comparison operator between them. This comparison operator may be one of the following:

Equal to (=);

Greater than (>);

Smaller than (<);

Greater than or equal to (); and

Smaller than or equal to ()

Mathematical sentences are used to express word sentences in a much shorter way, where words are replaced with math symbols.

A formula is a fact or a rule written in mathematical symbols. It contains a set of instructions on how to calculate an unknown quantity in terms of one or more known ones. The unknown quantity (otherwise known as the independent variable) is related to the known ones (dependent variables) through the equal sign ' = '.

Variables in formulas are combined with each other through mathematical operators such as addition, subtraction, multiplication, division, raise in power, logarithm, exponentiation, etc. Only the multiplication symbol ('·' or '×') is not written in a formula but is implied. Likewise, the division symbol (÷) is replaced by the fraction bar ('-' or '/').

We can either create a formula by reading and interpreting the description or interpret a formula in order to express in words the phenomenon described by it.

We use formulas to express scientific phenomena and also to describe daily activities in a shorter way, especially when these activities are recurring and have the same routine. The next step after correctly writing a formula is to substitute the known variables in it. In this way, we open the path to the calculation of the unknown quantity.

The steps one has to follow when dealing with formulas are:

Step 1: Identify the variables that are present in the situation under consideration.

Step 2: Assign a different letter to every variable including the one you are going to calculate.

Step 3: Write down the correct formula by including all variables identified in the first step.

Step 4: Substitute the other variables with numbers and calculate the value of the variable you are interested in by using the BEDMAS (PEMDAS) rule.

Wordy problems contain the necessary information to produce one or more formula; you just have to identify the variables participating in the event.

Sometimes, the independent variable in a formula is known and the value of one of dependent variables is required. In this case, we need to find a new formula based on the original one but which expresses the new unknown quantity in terms of the known ones. This is known as the inverse formula.

Whats next?

Enjoy the "Writing Formulas and Substituting in a Formula" revision notes? People who liked the "Writing Formulas and Substituting in a Formula" revision notes found the following resources useful:

  1. Revision Notes Feedback. Helps other - Leave a rating for this revision notes (see below)
  2. Formulas Math tutorial: Writing Formulas and Substituting in a Formula. Read the Writing Formulas and Substituting in a Formula math tutorial and build your math knowledge of Formulas
  3. Formulas Practice Questions: Writing Formulas and Substituting in a Formula. Test and improve your knowledge of Writing Formulas and Substituting in a Formula with example questins and answers
  4. Check your calculations for Formulas questions with our excellent Formulas calculators which contain full equations and calculations clearly displayed line by line. See the Formulas Calculators by iCalculator™ below.
  5. Continuing learning formulas - read our next math tutorial: Types of Formulas. Rearranging Formulas

Help others Learning Math just like you

[ 4 Votes ]

We hope you found this Math tutorial "Writing Formulas and Substituting in a Formula" useful. If you did it would be great if you could spare the time to rate this math tutorial (simply click on the number of stars that match your assessment of this math learning aide) and/or share on social media, this helps us identify popular tutorials and calculators and expand our free learning resources to support our users around the world have free access to expand their knowledge of math and other disciplines.

Formulas Calculators by iCalculator™