The title pretty much sums it up. Which of the following sentences is correct?
"A group of five-to-nine-year-olds did it."
"A group of five- to nine-year-olds did it."
Moreover, would it change anything if the numbers were bigger, meaning that I'd have to use them as numerals (following the Chicago Manual of Style, which states you should use numerals for numbers over a hundred)? For instance:
"A group of ninety-nine-to-101-year-olds did it."
"A group of ninety-nine- to 101-year-olds did it."
On a related note, would simply exchanging the "to" for an en-dash solve the problem? As in:
"A group of five–nine-year-olds did it" or "A group of ninety-nine—101-year-olds did it"? (Using an en-dash between the numbers and an hyphen between the numbers and the nouns and between the nouns themselves.)