Supplementary angles sum up to 180°, suppose the supplement of 161° is x. Then
161+x=180
solving for x we subtract 161 from both sides
161-161+x=180-161
x=19
thus the supplement is 19°
You will have 233 animals left.
When writing the equation keep in mind that 7 + x is said as a term that is squared so it has to be squared while it's still together; (7 + x)².
2, 3, 5 and 7 the the first 4 prime numbers