The calculation results are as follows:

Reading room area:12.6× 7.3 = 91.98m2.

1 brick area: 0.9× 0.9 = 0.8 1m2.

100 brick area: 0.81×100 = 81m2.

130 brick area: 0.81×130 =105.3m2.

Answer: 100 tiles are not enough, and 130 tiles are enough.

Extended data:

Multiply the product of several numbers by a number so that any factor in the product can be multiplied by this number and then multiplied by other numbers. For example: (25×3 × 9)×4=25×4×3×9=2700.

Multiply a number by the difference between two numbers, and you can multiply the minuend and the minuend by this number respectively, and then subtract the product. For example: (137-125) × 8 =137× 8-125× 8 = 96.