This video shows how to locate and plot a decimal number on a number line. Practice problems are available. [1:39]

This video shows how to write a number in the hundred millions in standard form from a description. Practice problems are available. [4:09]

This video explains place value in decimal numbers. Practice problems are available. [4:00]

Sal shows 42 as 4 tens and 2 ones using a visual demonstration. Includes a video, transcript, and question and answer section. [4:18]

Sal uses the number 37 to explain why we use a 'ones place' and a 'tens place' when writing numbers. Includes a video, transcript, and question and answer section. [5:58]

Sal compares 394 and 397 and then writes the expression using < or >. Includes a video, transcript, and question and answer section. [2:04]

Sal shows 25 as 2 tens and 5 ones using a visual demonstration. Includes a video, transcript, and question and answer section. [2:54]

Sal looks at the 1 in each teen number and thinks about what it really means. Includes a video, transcript, and question and answer section. [2:59]

Sal breaks the number 18 into 10 and 8 using monkeys. Includes a video, transcript, and question and answer section. [2:57]

Sal shows how to subtract 357-251 (without regrouping) using place value. Includes a video, transcript, and question and answer section. [2:56]

Sal demonstrates visually how to subtract 3-digit numbers by subtracting ones, tens, and hundreds. Includes a video, transcript, and question and answer section. [3:11]

Sal shows some techniques for doing mental addition, such as making groups of 10 and 100. Includes a video, transcript, and question and answer section. [7:27]

Sal rewrites three-digit addition problems to make them easier to solve. Includes a video, transcript, and question and answer section. [3:57]

Sal subtracts 1, 10, or 100 from a number using a visual demonstration. Includes a video, transcript, and question and answer section. [4:10]

Sal shows ways to break up three-digit addition problems using place value. Includes a video, transcript, and question and answer section. [3:41]

Sal demonstrates how to subtract 23 from 65 (without regrouping) by thinking about tens and ones. Includes a video, transcript, and question and answer section. [2:36]

Sal subtracts 4 from 46 by thinking about place value. Includes a video, transcript, and question and answer section. [2:44]

Sal demonstrates how to subtract 40 from 65 by thinking about place value. Includes a video, transcript, and question and answer section. [2:36]

Sal demonstrates the difference between subtracting 1 and subtracting 10 from 27. Includes a video, transcript, and question and answer section. [2:31]

Sal visually demonstrates how to add 327 + 251 (without regrouping) using place value. Includes a video, transcript, and question and answer section. [2:39]

Sal adds 1, 10, or 100 to 235. Includes a video, transcript, and question and answer section. [3:58]

Sal adds 3-digit numbers by adding ones, tens, and hundreds. Includes a video, transcript, and question and answer section. [3:36]

Sal shows various ways of subtracting 25 from 83 by thinking about tens and ones. Includes a video, transcript, and question and answer section. [5:26]

Sal subtracts two-digit numbers (without regrouping) by thinking about tens and ones. Includes a video, transcript, and question and answer section. [2:20]