Maths

Number
1
Activity 11: Understanding errors
OBJECTIVE: To understand how errors accumulate when results are added and subtracted
1. For l = (47·3 ± 0·1) cm and d = (34·7 ± 0·1) cm, complete the table.
Accumulated absolute error
in cm
Percentage error correct to
one decimal place
l + d =
cm
l − d =
cm
2. For m 1
= (32 ± 5) g and m 2
= (27 ± 5) g, complete the table.
Accumulated absolute error
in g
Percentage error correct to
nearest percentage
m 1
+ m 2
=
g
m 1
− m 2
=
g
3. For T 1
= (27·6 ± 0·2)°C and T 2
= (15·3 ± 0·2)°C, complete the table.
Accumulated absolute error
in °C
Percentage error correct to
nearest percentage
T 1
+ T 2
= °C
T 1
− T 2
= °C
4. The lengths l and d are measured in cm.
l = (4·2 ± 0·1) cm
l
d = (5·3 ± 0·1) cm
Evaluate the following, giving your answers with
their absolute errors.
d
(i) d + l =
(ii) d − l =
13