Using Letters to Represent Numbers

In Mathematics, we use letters of the alphabet to stand for numbers instead of boxes.

We write \( \scriptsize 10 \: + \: x \)instead of \( \scriptsize 10 \: + \: \boxed{?}\).

We can use any letter e.g. a, b, c, t, y, z etc.

Example 1.2.1:

Each sentence is true. Find the number that each letter stands for.

i. \( \scriptsize x = 2 + 7 \\ \rightarrow \scriptsize x = 9 \)

ii. \( \scriptsize y = 14\: – \: 4 \\ \rightarrow \scriptsize y = 10 \)

iii. \( \scriptsize 12 + 8 = P \\ \rightarrow \scriptsize P = 20 \)

iv. \( \scriptsize 2 + m = 5 \\ \rightarrow \scriptsize m = 5 \: – \: 2 \\ \rightarrow \scriptsize m = 3 \)

v. …