From twenty on, Portuguese builds numbers like bricks: the ten, then e (and), then the unit. First, the tens:

Number	Portuguese	Number	Portuguese
20	vinte	60	sessenta
30	trinta	70	setenta
40	quarenta	80	oitenta
50	cinquenta	90	noventa

Everything in between follows one pattern — and the e is never skipped:

• 21 vinte e um · 35 trinta e cinco · 48 quarenta e oito · 99 noventa e nove

100 is cem on its own — cem reais, a hundred reais. It only becomes cento when more follows: 101 cento e um.