The same three

About this video

In our numbers, a digit's value depends on where it stands. This short animation takes a single 3 and slides it to the left, one place at a time, through the ones, tens, hundreds and thousands. The digit never changes, but its value does: 3, then 30, then 300, then 3,000. Each place is worth ten times the place to its right.

Why ten? Because ten ones bundle into one ten, and ten tens bundle into one hundred, and so on, and each bundle gets its own place. The video shows the bundles too: ten dots become one bar, ten bars become one square. Last, it looks at the number 305. There are no tens in it, but the tens place can't just be left out. The zero holds it open. Take the zero away and the 3 slides into the tens place, so 305 turns into 35, a much smaller number. That job, keeping an empty place, is what makes zero so important in writing numbers. This video goes with the Ones, Tens and Hundreds lesson of Numbers Level 1 on Knaph.

Transcript

1. 0:00Is a three always worth three?
2. 0:04Slide it one place left, and it's worth ten times more. Thirty, three hundred, three thousand.
3. 0:11Ten ones make a ten. Ten tens make a hundred.
4. 0:17In three hundred and five, zero holds the tens open.
5. 0:21Leave it out, and you get thirty-five.
6. 0:25A digit is worth its place.