Three-digit Numbers
A three-digit number is built from three places: hundreds, tens, and ones. For example, 365 means three 100s, six 10s, and five 1s, the same as 300 plus 60 plus 5. Apartment numbers and page numbers often go past 100; the same digit is worth a different amount depending on where it sits, and that is what place value means. Change the number with the slider, look at how many blocks sit in the hundreds, tens, and ones columns, and compare two numbers by the length of their bars.
A digit is not worth the same amount in every slot. Put 3 in the hundreds slot and it is 300; put that same 3 in the ones slot and it is just 3. When you write a three-digit number, the left slot is hundreds, the middle is tens, and the right is ones, so you can split the number into how many 100s, 10s, and 1s you gathered. You need that split first, because later when you compare two numbers you are not asking which digit looks bigger. You are asking which slot is carrying more.
At the top of the first picture the three-digit number from the slider is written large, and below it the hundreds, tens, and ones sit in three columns. The left column holds gold squares labeled 100, as many as the hundreds digit. The middle holds tall blue sticks for the tens digit, and the right holds green dots for the ones digit. The equation at the bottom is hundreds count × 100 + tens count × 10 + ones count × 1, matching the number above. Change the slider and only those counts are drawn again; the squares, sticks, and dots stay where they are. In the second picture the two numbers are drawn as bars scaled against 999, and underneath you see both numbers with >, <, or = between them.
It is easy to pick the number that shows a 9 in the ones place and call that the larger one. Size for a three-digit number starts at the left slot, and if the hundreds digits differ that side is already larger. You only look at the tens when the hundreds match, and only then at the ones. A 9 in the ones slot is just 9; a 4 in the other number's hundreds slot is 400. How big the written digit looks and how much that slot is worth are not the same question.