Let's translate from English to math. :)
First, we're going to give some nicknames. Let's give "the number of goats" the nickname G. Let's give "the number of chickens" the nickname C, and let's give "the number of alpacas" the nickname A.
Now, let's take the first part of the sentence and translate from English to math:
"The product of the number of goats and the number of chickens" --> The product of G and C
The word "product" in math looks like ×.
So, let's write "The product of the number of goats and the number of chickens" as G × C
Now for the second part of the sentence! Remember that you can think of the English word "percent" as two words "per" and "cent."
Think of "per" in math as the fraction bar ⁄, and "cent" as 100, just like there are 100 cents in a dollar.
So, if we wanted to write 40 percent in math, we would put: 40 ⁄ 100. If we write this as a decimal, it would look like 0.40 or 0.4.
The word "of" in math always ×, like times.
So, let's write "40 percent of the number of alpacas" as 0.4 × A
The last word we have to translate from English to math is the word "is." We write this in math with an equals sign =
So, the whole English sentence "The product of the number of goats and the number of chickens is 40 percent of the number of alpacas" translated into a math sentence would look like:
G × C = 0.4 × A
There you go! I hope this helps. :)