3.6 Relating Letters to Numbers - Multiplying and Dividing
We will now repeat for x and ÷ what we did for + and - on page 6/77.
| Here is a true statement, 5 x 2 = 10, which can be rewritten as a division 5 = |
10 |
or 2 = |
10 |
| 2 |
5 |
| Using letters: a x b = c, which can be written as a division a = |
c |
or b = |
c |
| b |
a |
As you see, the pattern is the same, where a replaces 5, b replaces 2 and c replaces 10.
Here's another example. We start with a division, which can be rewritten
as a multiplication
and then a different division:
| 4 = | 12 |
which rearranges to 12 = 4 x 3 and then 3 = | 12 |
3 |
4 |
Replacing 4 by p, 12 by r and 3 by s we get
| p = | r |
which rearranges to r = p x s and then s = | r |
s |
p |
