No.2 pencils are widely used, but you may not know what the number actually refers to. This video explains how pencils developed into their modern form and the significance of the labeled numbers.

More clay in the mixture makes the lead harder. A harder lead has a higher number. Pencils are numbered from 1-3 but most people use a number 2. Harder lead makes a lighter mark and softer lead makes ...

25 has 2 tens and 5 ones so we add 2 packets of pencils to the tens column and 5 marbles to the ones column. Now let's add the second number to the place value chart. 33 has 3 tens and 3 ones so ...