Error is the difference between a true value and an estimate, or approximation, of that value
Step 1: (a) Find the error when 7.2 is given to 1 significant figure
true value = 7.2
estimate = 7 (to 1 s.f.)
Therefore,
error = 7.2 - 7 = 0.2
error = 0.2
Step 2: (d) Find the error when 7.56 is given to 1 significant figure
true value = 7.56
estimate = 7 (to 1 s.f.)
Therefore,
error = 7.56 - 7 = 0.56
error = 0.56
Step 3: (b) Find the error when 8.4 is given to 1 significant figure
true value = 8.4
estimate = 8 (to 1 s.f.)
Therefore,
error = 8.4 - 8 = 0.4
error = 0.4
Step 4: (e) Find the error when 8888 is given to 1 significant figure
true value = 8888
estimate = 8000 (to 1 s.f.)
Therefore,
error = 8888 - 8000 = 888
error = 888
Step 5: (c) Find the error when 10.21 is given to 1 significant figure
true value = 10.21
estimate = 10 (to 1 s.f.)
Therefore,
error = 10.21 - 10 = 0.21
error = 0.21
Step 6: (f) Find the error when 13012 is given to 1 significant figure
true value = 13012
estimate = 10000 (to 1 s.f.)
Therefore,
error = 13012 - 10000 = 3012
error = 3012