Since we have 2 Standard size's of Bricks i.e,
i) 19x9x9 (in cm) &
ii) 20x10x10 (in cm)
For both these sizes of bricks we go for 10mm thick mortar
joint for all faces of the brick so the size of brick
changes to 21x11x11 and 20x10x10 respectively.
Now to calculate number of bricks in 1 Cu.M.
i) for 19x9x9: =(1 in Cu.M)/((0.20x0.10x0.10) in Cu.M)

The standard size of brick we come across daily
construction work is 225*125*75 (in MM. The volume of 1
brick is equal to 0.002 mm3. So, for 1 m3 the number of
brick will be equal to 1/0.002 i.e. the answer is 500.

brick size 22.7x11.4x7.6 (cm)
with 10 mm mortar joint its size 23.7x12.4x8.6
so brick nos = quantity of brick work/size of brick with mortar
=1/0.237x0.124x0.086
=395
quantity of mortar
volume of brick for one m3
=395x0.227x0.114x0.076
=0.78 m so volume of wet mortar is =1-0.78=0.22 m3
volume of dry mortar=0.22/0.80 =0.275 thus it is 0.3 m3
proportion : 1:3 cement=0.3/1+3
=.075
=2.14 bags
sand = .3/4 x4
=0.018 m3

Simple method according to my view.........
BRICK SIZE=0.2*0.1*0.1
By multiplting it you will get 0.002
Now you want to find for 1m3
Divide 1m3/0.002 = 1 / 0.002
THEN YOU WILL GET THE ANSWER
AS. 500.......thats it.............