Conversion Factor and Rules for operating Integer sign

Length    
1 m      = 100 cm
1 m      = 1000 mm 
1 m      = 39.37 inch
1 m      = 3.28 ft
1 m      = 1.09 yards
1 cm    = 0.3937 inch
1 inch  = 2.540 cm
1 ft      = 12 inches 
1 ft      = 30.48 cm
1 km   = 1000 m 
1 km   = 0.621 mile
1 yard = 3 feet    
1 mile (mi)  = 1.609 km 
1 mile (mi)  = 5,280 feet 
1 mile (mi)  = 1760 yards
1 hectometer  = 100 m
1 decameter   = 10 m

Mass  
1 gram = 1000 milligrams
1 kg     = 1000 grams 
1 ton    = 1000 kg
1 ton    = 10 quintals
1 quintal = 100 kg
1 pound  = 455 grams
1 kg        = 2.2 pounds 
1 kg        = 0.06852 slug
1 lb     = 453.6 gm 
1 lb     = 0.03108 slug
1 slug = 32.174 Ib
1 slug   = 14.59 kg
1 tola   = 12 grams
1 chhatak = 54 grams  

Speed  
1km/hr   = 0.2778 m/sec    
1km⁄hr   = 0.6214 mi⁄hr
1km/hr   = 0.9113 ft/sec
1mi/hr   = 1.467 ft∕sec⁡      
1 mi⁄hr   =1.609km/hr   
1 mi/hr  = 0.4470 m/sec  

Time  
1 hour  = 60 minutes
1 hour  = 3600 seconds
1 minute = 60 seconds
1 day  = 24 hours
1 day  = 86400 seconds
1 day  = 1440 minutes
1 week   = 7 days
1 month = 30 days
1 year = 12 months
1 common year = 365 days
1 leap year = 366 days
1 decade    = 10 years
1 century   = 100 years
1 millennium = 1000 years
  
Counting  
1 dozen = 12 units
1 quire (dista) = 24 sheets
1 short ream = 480 sheets
1 long ream = 500 sheets
1 gross = 12 dozens  or 144 sheets

Rules for operating Integer sign 
Addition
(+)+(+) = +
(-)+(-)   = -
(+)+(-)  = ±
(-)+(+)  = ±

Subtraction
(+)-(+) = ±
(-)-(-)   = ±
(+)-(-)  = +
(-)-(+)  = -

Multiplication
(+)×(+) = +
(-)×(-)   = +
(+)×(-)  = -
(-)×(+)  = -

Division
(+)÷(+) = +
(-)÷(-)   = +
(+)÷(-)  = -
(-)÷(+)  = -  

Note: In case of addition or subtraction we take

            “Sign of bigger integer”.