1. size of each brick = 9"x4.5"x3".let us convert into inches as 0.75x0.325x0.25

2. hence volume of each brick = 0.0703 cft.

3. hence the volume of bricks in 100 cft without mortar=100/0.0703=1422.22 no of bricks.

4. the volume of mortar in 100 cft brick work =10% volume

5. so the mortar occupy 10/100*1422=142.40 no of bricks

6. hence the no of bricks required for 100 cft of brick work = total no of bricks- occupied area of the mortar - 1442-142=1280 mos of bricks

7. add 5% contingencies and breakage 5% of 1422 briks - 5/100*1422=71 no of bricks

8. hence the total no of bricks required for 100 cft brick work =1280+71=1351 briks

9. round of figure of bricks required for 100 cft brick work = 1350 nos ( modular bricks) in case of brick sizes varies the quantity also vary according to the sizes