In grade 3, students learn about place value. Place value refers to the value of a digit based on its position in a number. The position of a digit determines its place value, such as ones, tens, hundreds, thousands, etc.

Here are some key concepts and skills related to place value that are typically taught in grade 3:

1. Understanding the value of digits: Students learn to identify the value of each digit in a number based on its position. For example, in the number 345, the digit 3 represents 300, the digit 4 represents 40, and the digit 5 represents 5.

2. Reading and writing numbers: Students practice reading and writing numbers in both standard form and expanded form. Expanded form breaks down a number into its place value components. For example, the number 345 can be written as 300 + 40 + 5 in expanded form.

3. Comparing and ordering numbers: Students learn to compare and order numbers based on their place value. They use symbols like < (less than), > (greater than), and = (equal to) to compare numbers. For example, they can compare 345 and 456 to determine which number is greater.

4. Rounding numbers: Students learn to round numbers to the nearest ten or hundred. They use place value to determine which digit to look at when rounding. For example, rounding 345 to the nearest ten would be 350, and rounding 345 to the nearest hundred would be 300.

5. Adding and subtracting numbers: Students use place value to add and subtract numbers. They learn to align digits based on their place value when performing these operations. For example, when adding 345 and 456, they align the ones place, tens place, and hundreds place to correctly add each digit.

These are some of the main concepts and skills related to place value that are typically covered in grade 3.