Australia (~7.69 million km²) is approximately 10.2 times larger than Zambia (~752,618 km²).
Therefore, you could fit **Zambia into Australia roughly 10 times** (with a little room to spare).
For context: Australia is the 6th largest country; Zambia ranks 39th. Australia is slightly smaller than the contiguous U.S.; Zambia is slightly larger than Texas.