+257 is the INternational Country Code for Burundi
257+420 = 677
357
257
Telephone country code +257 (dialed as 00 257 from many places) is the African nation of Burundi.(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
256 + 1 = 257
69 + 188 = 257
Telephone country codes never begin with zero.Country code +257, dialed as 00 257 from many places, is Burundi (Africa).Country code +57, dialed as 002 57 from many places, is Colombia (South America).To avoid confusion, it is best to write an international telephone number in correct international format, beginning with the plus symbol and the correct telephone country code (e.g., +257 or +57), omitting any dialing prefix.(The plus signmeans "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
It is 771000 + y
if 6x=42 whats the value of x
257 MPH, plus 1,001 Horsepower.
600 + 250 = 850
111011000 (decimal 472). The sum is 257+215.