It gives the perimeter of 14 mm and if it is 3 mm tall, times that by 2 to get 6 for the total of both side then subtract 6 from 14 and you get 8 and then divide that by 2
Answer is 4 mm wide for the two sides
51,000
5 in the ten thousands,
The thousands value is 1, the hundreds is 4 (less than 5 so we round down)
Turn fraction into a decimal.
-2 1/2 = -2.5
Remember that when you subtract a negative number it automatically changes it to adding a positive number.
-6 + 2.5 = -3.5
Hope This Helped! Good Luck!