Know Your Limits!
These measurements have been rounded to the nearest whole unit. State the upper and lower
bounds and then write them in an inequality (remember that the upper bound is not included).
Measurement
Lower bound
Upper bound
Ex
89 m
88.5 m
89.5 m
1
72 cm
2
4 kg
3
108 mm
4
364 ml
5
481 g
These measurements have been rounded to the nearest tenth of a unit. State the upper and
lower bounds and then write them in an inequality.
Measurement
Lower bound
Upper bound
Ex
4.8 kg
4.75 kg
4.85 kg
1
6.9 km
2
55.4 g
3
3.2
4
12.5 cm
5
888.3 m
l
Know Your Limits!
Extension task
The sides of a rectangle have been measured and rounded to the nearest whole unit.
(a) Work out the smallest possible perimeter
(b) Work out the largest possible perimeter
(c) Work out the smallest possible area
(d) Work out the largest possible area
Example
Lower bounds
Upper bounds
Rectangle: length 7 cm, width 5 cm
6.5 cm & 4.5 cm
7.5 cm & 5.5 cm
Smallest perimeter = (2 x 6.5) + (2 x 4.5) = 22 cm
Largest perimeter = (2 x 7.5) + (2 x 5.5) = 26 cm
Smallest area = 6.5 x 4.5 = 29.25 cm2
Largest area = 7.5 x 5.5 = 41.25 cm2
1.
2.
3m
12 m