Answer:
See below. Veronica's thinking is incorrect. I've included what she is thinking, but the correct thinking is more useful, as noted below.
Step-by-step explanation:
398 is 2 less than 400. Veronica needs to remove two groups of 18.
I don't know what Veronica is thinking, other than:
(398 x 18) = (400*18 - 18)
She should be thinking:
(398 x 18) = (400 x 18) - (2*18). The "2" is for the two extra groups of 18 that she will have when multiplying 400 x 18, instead of 398 x 18.
