What is length?
Length is a measure of one-dimensional space.
(2) Common length units
* kilometers (km) * meters (m) * decimeters (dm) * centimeters (cm) * millimeters (mm) * microns (um)
(3) Conversion between units
* 1mm = 1000mm * 1cm = 10mm * 1cm = 1cm * 1m = 1000mm * 1km。
Second, the area
(1) What is the area?
Area is the size of the plane occupied by an object. The measurement of the surface of three-dimensional objects is generally called surface area.
(2) Public area unit
* square millimeter * square centimeter * square decimeter * square meter * square kilometer
(3) conversion of area units
* 1 cm2 =100mm2 * 1 cm2 =1cm2 * 1 m2 =100mm2.
* 1 ha = 10000 m2 * 1 km2 = 100 ha.
Third, quantity and quantity
(1) What are volume and volume?
Volume is the size of the space occupied by an object.
Volume, the volume of objects that can be accommodated in boxes, oil drums, warehouses, etc. , usually called their volume.
(2) Common units
1 unit of volume
* cubic meter * cubic decimeter * cubic centimeter
2 unit of volume * L * mL
(3) Unit conversion
1 unit of volume
* 1 m3 = 1000 cubic decimeter; * 1 cubic decimeter = 1000 cubic centimeter
2 unit of volume
* 1 l = 1000 ml; * 1 l = 1 m3; * 1 ml = 1 cm3
Fourth, quality.
What is quality?
Mass refers to the weight of an object.
(2) Common units
* tons * kilograms * grams
(3) General conversion
* one ton = 1000 kg; * 1 kg =1000g
Verb (short for verb) time
(1) What is time?
Refers to a period of time with a starting point and an ending point.
(2) Common units
Century, year, month, day, hour, minute and second.
(3) Unit conversion
* 1 century = 100 year; * 1 year = average number of years of 365 days; * One year =366 days leap year
* January, Wednesday, Friday, July, August, October and December are big months, with 3 1 day.
* Four, six, nine and eleven are abortions. Abortion lasts for 30 days.
* There are 28 days in February in a normal year and 29 days in February in a leap year.
* 1 day = 24 hours * 1 hour =60 minutes * 1 minute =60 seconds.
Intransitive verb currency
(1) What is money?
Money is a special commodity, which acts as the equivalent of all commodities. Money is a general representative of value and can buy any other commodity.
(2) Common units
* Yuan * Jiao * fen
(3) Unit conversion
* 1 yuan = 10 angle * 1 angle = 10 point.