1. **State the problem:** We need to find the numbers $A$ and $B$ such that: - $7 \times A = 21$ - $7 + B = 21$ 2. **Formula and rules:** - For multiplication: If $a \times x = b$, then $x = \frac{b}{a}$. - For addition: If $a + x = b$, then $x = b - a$. 3. **Solve for $A$:** $$7 \times A = 21$$ Divide both sides by 7: $$\cancel{7} \times A = \frac{21}{\cancel{7}}$$ $$A = 3$$ 4. **Solve for $B$:** $$7 + B = 21$$ Subtract 7 from both sides: $$\cancel{7} + B = 21 - \cancel{7}$$ $$B = 14$$ 5. **Final answers:** - $A = 3$ - $B = 14$