Questions & Answers about Yksi ja kaksi on kolme.
In English we often say One and two ARE three. Why does this sentence use the singular on instead of the plural ovat?
In Finnish, math equations always use the singular verb on. The equation is treated as one single fact, so you never use the plural form here.
Is ja the usual way to express addition in Finnish?
ja means and, which is very common in everyday speech for simple addition. If you want to use the exact mathematical term for plus, you can use the word plus: yksi plus kaksi on kolme.
Are the numbers in this sentence in their basic form?
Yes! When you are just stating a math equation or counting, numbers stay in their basic dictionary form. You do not need to add any special grammar endings to them.