Ah, I wasn't thinking of calculators that let you type in a full expression. When I was in school, only fancy graphing calculators had that feature. A typical scientific calculator didn't have juxtaposition, so you'd have to enter 6÷2(1+2) as 6÷2×(1+2), and you'd get 9 as the answer because ÷ and × have equal precedence and just go left to right.
you’d get 9 as the answer because ÷ and × have equal precedence and just go left to right
Well, more precisely you broke up the single term 2(1+2) into 2 terms - 2 and (1+2) - when you inserted the multiplication symbol, which sends the (1+2) from being in the denominator to being in the numerator. Terms are separated by operators and joined by grouping symbols.