### Video Transcript

30 times 40 equals what?

We can use a known fact to help us calculate the answer mentally. We know that three times four is 12. 30 is 10 times greater than three. So 30 times four would be 120. 120 is 10 times greater than 12. If 30 times four is 120, 30 times 40 will be 10 times greater. 30 times 40 is 1200.

We could calculate the answer in another way, using the known fact three times four equals 12. If three times four is 12, then three times 40 equals 120 because 40 is 10 times greater than four. Three times 40 is 120. So 30 times 40 will be 10 times bigger, 1200. 30 times 40 equals 1200.

We used a known fact, three times four equals 12, to help us calculate 30 times four. And then, we calculated 30 times 40. In our second method, we used the same known fact three times four is 12 to help us calculate three times 40 which is 120. And then, we calculated that 30 times 40 is 1200. Both methods gave us the same answer.