The phrase "approximately two to three" is correct and usable in written English.
It can be used when providing an estimate or approximation of a quantity or range.
Example: "The project will take approximately two to three weeks to complete."
Alternatives: "roughly two to three" or "about two to three".
One customer cancelled this morning – a project that would have been approximately two to three weeks' work for us.
Qantas, the Australian carrier, said it would take "approximately two to three weeks to clear the current backlog".
The object was described as being metallic in appearance and triangular in shape, approximately two to three meters across the base and approximately two meters high.
After she had finished, I told her that I didn't want another card, that I received approximately two to three calls per night from various telemarketers and that I never bought anything over the phone.
In 2012, The Government Accountability Office found that the strict voter-I.D. laws in Kansas and Tennessee had reduced voter turnout from 2008 to 2012 by approximately two to three per cent.
A phagemid library designed to result in approximately two to three mutations per lipase gene was then constructed.
Hypoxic-ischemic encephalopathy (HIE) is an important cause of acute neurologic injury at birth, affecting approximately two to three cases per 1000 full-term live births.
Australopithecus africanus, which lived approximately two to three million years ago, had a fully modern foot and probably strode.
Of the approximately two to three thousand volumes of Byzantine literature that survive, only three hundred and thirty consist of secular poetry, history, science and pseudo-science.
"Immunization averts approximately two to three million deaths each year and is an essential tool in public health.
If eligible, they would be asked to provide informed consent to participate in the study, which would last approximately two-to-three hours.
