" a difference " means subtract
5y - 7......u have 2 terms (5y and 7)...and it is the difference of 2 terms.
so ur answer is : 5y - 7
The errors are that she is just multiplying incorrectly.
10* 1.75 = 17.5
100* 1.75= 175
1000* 1.75 = 1750
When you are multiplying by tens (hundreds and thousands are also considered tens since they are just 10*10 and 10*10*10), you should just be moving the decimal place forward one place.
This goes back to very basic math when you are learning place values.
5 since both numbers are divisible by 5 and not by any smaller number
