The student is correct that 83.8 - 5 is greater than one, as 1 is less than 83.8 - 5 by 77.8 units
1 - Find out what the value is
83.8 - 5 = 78.8
2 - Compare it to 1
To get to 78.8 from 1 we must increase 1 by 77.8 meaning 78.8 is 77.8 more than 1 therefore is greater than 1.
Hope this helps