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. Far East Journal of Mathematical Education, [S. l.], v. 22, p. 29–32, 2022. DOI: 10.17654/0973563122006. Disponível em: https://pphmjopenaccess.com/fejme/article/view/666. Acesso em: 5 jan. 2026.