Learn French: Il y a six ou sept problèmes difficiles. - There are six or seven difficult problems.

Normally, six is pronounced like 'cease'. But when it comes right before a word starting with a vowel sound, like ou (or), the 'x' connects to it and makes a 'z' sound. So here, six ou sounds like 'seez oo'. If it were placed before a word starting with a consonant, the 'x' would be completely silent!

Is the 'p' in sept pronounced?

No, the 'p' in sept is always silent. The word sounds exactly like the English word 'set'.

Doesn't il y a mean 'there is'? Why is it used here for 'there are'?

In French, il y a is a fixed phrase that translates to both 'there is' and 'there are'. It never changes to a plural form, even though we are talking about multiple problems in this sentence.

Why does difficiles come after problèmes?

In English, we say 'difficult problems' (adjective before noun). In French, most adjectives, including difficiles, go right after the noun they describe. Notice that both problèmes and difficiles get an -s at the end because there is more than one, though this -s is silent when spoken.