How many sqm do my 18 limestone slabs that are 40x40cm become?

[Marie vS]

I'm completely blank, how do I calculate how many square meters my 18 limestone tiles cover? The tiles are 40cm x 40cm. Thankful for help!

 

[Dan_Johansson]

0.4 x 0.4 x 18 = 2.88 sqm

 

[lunnabo]

I'm completely blank, how do I calculate how many square meters my 18 limestone slabs are enough for, approximately. The slabs are 40cm x 40cm.
Grateful for help!

Five slabs in a row make two meters plus the joint.
On the fourth row, the slabs run out after the 3rd slab.