Note that sechs drops the final “s” and sieben drops the “en” when followed by the suffixes -zehn and -
ig.
You also drop the “s” when
combining eins with other numbers (eg. einhundert).
Please also note the special forms zwanzig (not
zweizig!)
and dreißig (the “z” is
replaced by “ß”).
36
German double-digit numbers are read
“from right to left”, starting with the second digit and
linking it to the first with “und”.
So the number 28 is achtundzwanzig, which reads literally as
“eight-and-twenty”
and the number 43 is dreiundvierzig (“three-and-forty”).