Dividing Letters in Algebra
(KS3, Year 7)
- A letter can be divided by a number. Write the letter as the numerator of a fraction, and the number as the denominator.
- A letter can be divided by a different letter. Write the letter you are dividing by (b) under the letter you are dividing (a).
Dividing Letters to Make Terms
A term is a collection of letters and numbers multiplied and/or divided together. In the examples above, the letter a has been divided by a number and the letter b to make terms. These divisions can be combined to make a more complicated term: how to divide termsDividing a Letter with the Same Letter
Dividing a letter with itself equals 1: Letters sometimes have exponents, which tell you how many times the letter is multiplied by itself. For example, a1 = a, a2 = a × a and a3 = a × a × a. When a letter with an exponent is divided by that same letter, we must subtract the exponents.- For example, imagine we wanted to divide a2 ÷ a. (Don't forget: if a letter does not have an exponent, it has an implicit exponent of 1): We can see why this works if we write out the term in full, rather than using exponent notation, remembering that a2 = a × a. Each a on the denominator cancels out an a on the numerator, leaving only one a:
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Imagine we wanted to divide a4 ÷ a2:
We can see why this works if we write out the term in full, remembering that
a4 = a × a × a × a and that a2 = a × a. Each a on the denominator cancels out an a on the numerator, leaving two a's:
Beware
Be Careful with Signs
Letters can have different signs: a + sign if they are positive, and a - sign if they are negative. Remember the rules for dividing different signs: Same signs give a plus: Different signs give a minus:Worksheet
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