There are 6 rows with 18 chairs in each row. In the center of the chairs, 4 rows of 6 chairs are brown. The rest of the chairs are blue. How many chairs are blue?

Multiply 6 times 18 and you get 108 chairs total. Subtract 6 by 4 and you get 2 rows left for blue. Multiply 4 by 6 and you get 24 in brown chairs all together. Then subtract 108 by 24 and you get 84 chairs all together for blue. So that means 2 rows with 42 blue chairs in each row.

(6 x 18) - (4 x 6) =

108 - 24 = 84 Blue Chairs