1. Let's clarify the problem: you want to understand how the numbers 7 and 21 were obtained. 2. Suppose we are dealing with multiplication or factors. Notice that 7 and 21 are related because 21 is $3 \times 7$. 3. This means 7 is a factor of 21. 4. If you had a number like 21, factoring it into prime factors: $$21 = 3 \times 7$$ 5. Alternatively, if 7 and 21 came up from solving an equation or context, please provide details so I can explain specifically. 6. But generally, 7 is a prime number, and 21 is its multiple by 3, which is why both appear together. 7. So, 7 and 21 are connected through multiplication where 21 is $3 \times 7$. Hence, that is how you get 7 and 21 related.