Answer:
What's the difference between a number track and a number line? A number track is a sequence of numbers, each inside its own square. ... Whereas, a number line is where the numbers are attached to markers on a line. This method of addition / subtraction comes later.
Let the integers be x - 1, x and x + 1, then
x - 1 + x + x + 1 = -42
3x = -42
x = -42/3 = -14
The three consectutive integers are -15, -14 and -13
Not 100% sure this is right but
60cm^2

P=Perimeter
L=Length
W=Width
Hints given are P= 76, L=20 so 2L=40
76=40+2w
76-40=2w
36=2w
18=w