## ESTIMATION

**Estimation** may be explained as a rough or sensible guess fo a **value** or calculation. Although, the estimated **value** is not correct, it gives us an idea of what the correct answer should be.

The common units of length are kilometer (km), meters (m), centimeters (cm), millimeters (mm).Mass = (Tonne, kilogram (kg) gramme (g). Capacity = (litre (l), centiliter (cl), militre(ml)

It is important to be able to choose the most appropriate metric units of measurement to use.

Example: To measure distance less than a metre, smaller units such as milimetre (mm), and centimeter are used to measure large distance, metre and kilometer (km) are used.

State the metric units of the length you would use to measure the following:

(a). Length of your class room = metre (m0

(b). Length of your fingers nail = milimetre (mm)

(c). your height = centimeter (cm)

(d) Distance between Lagos and kaduna = kilimetre (km)

(e). the height of a building =Â metre (m)

*SIGNIFICANT: TO ROUNDOFF A NUMBER CHANGE 0,1,2,3,4 TO 0 WHILE 5,6,7,8,9 TO 1 AND ADD IT TO THE NEXT NUMBER*

Example 1: round off 492.763 to (a) 3 s.f (b) 3 s.f (c) 2 d.p (d) 4 d.p

Solution:

(a). 492.763 = 49 (since the third number is 2 it has change to zero)

(b). 492.763 = 493 (the 2 as change to 3 because 7 as change to 1 and been added to 2 to become 3)

(c).492.763 = 492.76 (in decimal point we count after the point).

(d). 492.763 = 492.7630(since the number is not upto 4d.p we add zero to it.)

See also