Question

What is the numerical expression of the sum of 3 fifteens and 4 twos and the model of it

Answer 1

When you say something like "three fifteents", you means that you have to consider the number 15 three times, so you're implicitly talking about multiplications.

So, "3 fifteens" means
`3\cdot 15` and in the same fashion "4 twos" means
`4\cdot 2`

Finally, "and" implies a sum, so the expression would be

`3\cdot 15+4\cdot 2`