we measured coins and these are the measurements i got. i dont get how to find the calculated avg thickness and im not sure if the whole table is right

Measurements And Significant Figures - Seager/Slaboph Table 1.8 (report) Correct Number of Decimal Places for Rectangle Calculated Perimeter 2 Calculated Perimeter Unrounded (cm) 3 50.8 Calculated Perimeter Rounded (cm) 50.80 31.00 12.20 47.80 X 2 Y 12.2 47.8 N C. Improving the significance of Measurements Table 1.9 (data) Measured diameter (cm) 2.00 Number of coins in stack 1 3 5 7 10 1.60 Measured thickness (cm) 80 1.00 Table 1.10 (report) Number of Coins in Stack Measured Stack Thickness (cm) Number of Sig. Figures in Measured Thickness 2 Correct Number of Sig. Figures in Calculated Avg. Thickness .10 Calculated Avg Thickness Unrounded (cm) Calculated Avg Thickness Rounded (cm) 1 0.10cm 2 3 5 60cm .800m 1.00cm 1.60cm 7 3 10 3 Measurements And Significant Figures - Seager/Slaboph Table 1.8 (report) Correct Number of Decimal Places for Rectangle Calculated Perimeter 2 Calculated Perimeter Unrounded (cm) 3 50.8 Calculated Perimeter Rounded (cm) 50.80 31.00 12.20 47.80 X 2 Y 12.2 47.8 N C. Improving the significance of Measurements Table 1.9 (data) Measured diameter (cm) 2.00 Number of coins in stack 1 3 5 7 10 1.60 Measured thickness (cm) 80 1.00 Table 1.10 (report) Number of Coins in Stack Measured Stack Thickness (cm) Number of Sig. Figures in Measured Thickness 2 Correct Number of Sig. Figures in Calculated Avg. Thickness .10 Calculated Avg Thickness Unrounded (cm) Calculated Avg Thickness Rounded (cm) 1 0.10cm 2 3 5 60cm .800m 1.00cm 1.60cm 7 3 10 3