Hi; question I have 25sqm to cover with paving slabs whicj are 400mmsquared. answer my answer is convert mm to m ie 0.4*0.4 = 0.16msquared then 25 / 0.16 = 156.25 slabs needed are far as I'm concerned this is correct? but I've just used an online calculator that tells me I need 150 slabs surely this is wrong? also I need to cover the same area with turf which is 1sqyard per roll. sqm to sqfeet divide by 0.0929 which gives 25 / 0.0929 = 269.1sqfeet. dividing by 9 because a yard is 9sqfeet gives 269.1 / 9 = 29.9 rolls I'm sure this is correct?Just need confirmation please.Thanks.