PROOF WITHOUT WORDS: $\frac{a}{b}=\frac{c}{d} \Rightarrow \frac{a}{b}=\frac{c}{d}=\frac{a \pm c}{b \pm d}$ IN THE RANGE OF NATURAL NUMBERS. (2022). Far East Journal of Mathematical Education, 22, 29-32. https://doi.org/10.17654/0973563122006