PLEASE HELP!!

Solving problems with hcf and lcm

A small gardening allotment has dimensions 221 cm by 153 cm.
David wants to see how many square based planting spaces he can make in this
allotment.
If he wants to divide this allotment space into squares with the greatest
possible side length, how many squares will there be in the allotment?

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.