Answer: The total change is 21.
Since you want to find the change from the lowest to highest, make it into a subtraction problem. First of all, take the smallest number in front of the largest.
20 -1
Next, add a minus sign in between, your equation should look like this:
20 - (-1) = x
Then, you cancel out the negative signs. After that you solve it
20 - (-1) -> 20 + 1.
Lastly, you add them together.
20 + 1 = 21.
In conclusion, the answer is 21.
I'm kind of thrown off for that negative sign, but I try it out in the one that makes sense is this one [ https://gyazo.com/192a76e70d2d46979691cabbf06e6c85 ] If you can better of explain where the negative sign will be great. Hope I helped.
She would've bought 7 bags of apples, I believe.