1) a calculator (electronic device that performs mathematical calculations)
2) a computer (device)
This is an example of the inherent lack of a well-built technical vocabulary in Vietnamese. Colloquially, for the sake of differentiation, máy vi tính (or just vi tính) can be used seldomly to refer to "computer". More technically, máy vi tính only refers to "microcomputer".
máy tính bỏ túi (“pocket calculator”) is a "fancy" term, chiefly used in the translations of the user's guides of some calculators, and documents published by the Ministry of Education and Training.
From Wiktionary: https://en.wiktionary.org/wiki/m%C3%A1y_t%C3%ADnh
Actually, in this course, we don't teach the word "mobile device", but some kinds of mobile devices such as điện thoại - phone/telephone, máy tính bảng - tablet/tab and máy tính - computer/calculator. Here are some other devices you may want to know.
- Điện thoại di động - mobile phone
- Máy tính xách tay - laptop
- Máy tính cầm tay/Máy tính bỏ túi or just simply Máy tính- calculator
- Điện thoại thông minh - smartphone
- Đồng hồ thông minh - smartwatch
- Thiết bị định hướng cá nhân - personal navigation device (PND)
Vietnamese vocabulary now lacks a lot of words for new terms in many fields. There are many ways to compensate for that shortfall (translate as a whole word or separate that word into parts then translate each part from English; Việt hoá * them in terms of pronunciation (pronounce them with Vietnamese phonological system) and orthography (shorten, write them with Vietnamese orthography); borrow words from some other languages like Chinese, Japanese, etc. or create new words for them) but the number of words that are created by these ways is still limited. People now tend to use original words from English but pronounce them with Vietnamese phonological and orthographical rules. Sometimes, they sounds really weird :)
* Việt hoá: make sth become "Vietnamese". I don't know if English has a word for this, maybe "Vietnamesize".