First, let's figure out the answer. Then, we will put it in the format shown.
234 is 10% less than previous year number.
Let the previous year number be "x", so we can say:
234 is 10% less than x
As equation, we can write:

** Note, 10% = 0.1
Let's solve the equation for x:

There were 260 nesting turtles in the sactuary last year.
Double Number Line
TableEquation