You have most likely seen a telephone number like +44 70xx xxx xxx, although the digits may have been grouped differently.
Telephone country code +44 is the United Kingdom, and numbers beginning with +44 70 are personal "follow-me" numbers that can be forwarded to anywhere in the world. These are special numbers which people or companies can use to manage their calls across several phones. For example, the owner of a Personal Number might set it to ring their home phone in the evening, and their mobile phone in the daytime. They are also sometimes used by people who do not want to reveal their real home or mobile phone number. Although there are legitimate users, they are also very popular with internet scammers. Rates for calls to these numbers may be substantially higher than for calls to ordinary geographic landline numbers in the UK.
(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.)
The telephone country code for Vietnam is +84. The area code for Ben Tre is 075, or +84 75 in international format.
Numbers beginning with +44 75 are mobiles in the UK.
The country code and area code of Gabes, Tunisia is 216, 75.
75% of 44= 75% * 44= 0.75 * 44= 33
The country code and area code of Ratanakiri, Cambodia is 855, (0)75.
The country code and area code of Paks, Hungary is 36, (06)75.
The country code and area code of Shwebo, Myanmar is 95, (0)75.
The country code and area code of Palpa, Nepal is 977, (0)75.
The country code and area code of Zaandam, Netherlands is 31, (0)75.
The country code and area code of Yola, Nigeria is 234, (0)75.
The country code and area code of Hoenau, Paraguay is 595, (0)75.
The country code and area code of Trang, Thailand is 66, (0)75.