One difficulty when reading out numbers in Mandarin is the zeros. In English, "101" is read "one hundred and one", but in Mandarin you say "一百*零一" (yī bǎi *líng yī) – "one hundred zero one". The rule, as in English, is that whenever there's a gap of one decimal place or more, you need to shove another word in to separate your units.
Filling in the gaps
Things start to get more interesting when you have several such gaps in a number. In English you only need to say "and" to point out the last gap in a number. So "10207" is just "ten thousand two hundred and seven". In Mandarin, however, you have to indicate every gap: "一万零*两百*零*七" (yī wàn *líng liǎng bǎi líng qī). This is like saying "ten thousand and two hundred and seven".
One zero per gap
Just as in English, no matter how many zeros there are, you only need to indicate the gap once, with one word. So the number 10001 ("ten thousand and one") is just "一万零*一" (yī wàn *líng yī). You don't need to read out all of the three zeros in the number. Neither do you need to indicate zeros on the end of a number – just as in English.
101: 一百零一 (yī bǎi líng yī)
208: 两百零八 (liǎng bǎi líng bā)
1005: 一千零五 (yī qiān líng wǔ)
10003: 一万零三 (yī wàn líng sān)
10509: 一万零五百零九 (yī wàn líng wǔ bǎi líng jiǔ)
100070: 十万零七十 (yī wàn líng qī shí)