How to correctly calculate the area of ​​a rectangle?

Question

Mathematics

Good afternoon!
Help me figure it out, you need to find out the area of ​​a rectangle 1.8 m by 0.6 m, in which there are 90 round holes with a diameter of 10 mm, express the result in meters.
I counted in two ways:
1 way - all values ​​​​in millimeters
I calculate the area of ​​\u200b\u200bthe circle using the formula PR 2 \u003d 3.14 * (5 * 5) \u003d 78.5 mm
Then I count S:
(1800 * 600) - (78.5 * 90 ) \u003d 1072935 I
translate the resulting value into meters (1072935 / 1000 \ u003d 1072.935 )
2 way - all values ​​\u200b\u200bin meters
I calculate the area of ​​\u200b\u200bthe circle using the formula PR 2 \u003d 3.14 * (0.005 * 0.005) \u003d 0.0000785 m
Then I calculate S:
(1.8*0.6)-(0.0000785*90) = 1.0729
as a result, 1072.935 is not equal to 1.0729
How to calculate correctly?

Answer 1

Not finished. 1 square meter is 1000*1000mm.
The resulting millimeters must be divided by a million.

Answer 2

1m^2 = (1000mm)^2 = 1000^2mm^2 = 1000000mm^2