Upper and Lower Bounds

Question 1:

When x = 6800 (2 s.f.) and
y = 24 (2 s.f.), find the lower bound of x + y

6773.5

Question 2:

When x = 1.811 (3 d.p.) and
y = 0.054 (3 d.p.), find the upper bound of x - y

1.758

Question 3:

When x = 0.4 (1 d.p.) and
y = 0.95 (2 d.p.), find the lower bound of x × y

0.33075

Question 4:

When x = 16.4 (1 d.p.) and
y = 0.715 (3 d.p.), find the lower bound of x ÷ y

22.851153039832