Learn Dutch: Wij hebben kleurrijke boeketten nodig, dus we schikken er zes mooie. - We need colorful bouquets, so we arrange six beautiful ones.

This is the quantitative er. Because we are stating a quantity (zes) of something we already mentioned (boeketten) without repeating the noun, we have to include er. It works a bit like saying "six of them" in English.

Why does "mooi" get an -e at the end to become "mooie"?

In this structure, the adjective stands alone without the noun right after it. When an adjective is used with quantitative er and a number to replace a noun like this, it always gets an -e ending. Think of the -e as representing the English word "ones" in "beautiful ones".

How does the phrase "nodig hebben" work in the first clause?

The Dutch equivalent of "to need" is nodig hebben. Just like a separable verb, the conjugated part (hebben) takes the normal second position in the sentence, while nodig gets pushed to the very end of the clause, placing the object (kleurrijke boeketten) in between them.

Why doesn't the word order change after "dus"?

The word dus (so) is a coordinating conjunction, which means it joins two independent clauses together without changing the word order. Because of this, the subject (we) and verb (schikken) in the second half of the sentence stay in their normal subject-verb order.