During June 1st in Garden Primary School, there were 130 calligraphy assignments in ten windows, and 15 calligraphy assignments in major windows.

Assume that all large and small windows have:

( 15× 10- 130)÷( 15- 10)

=20÷5

=4 (pieces)

Then the big window is: 10-4=6 (pieces)

There are four small windows and six big windows.