Number Sense and Operations for Grade 3
Understanding Place Value
Place value is the value of each digit in a number. For example, in the number 345, the digit 3 is in the hundreds place, the digit 4 is in the tens place, and the digit 5 is in the ones place. Understanding place value helps in reading, writing, and comparing numbers.
Example: The number 789 can be broken down as:
- 7 in the hundreds place: 700
- 8 in the tens place: 80
- 9 in the ones place: 9
So, 789 = 700 + 80 + 9.
Comparing Numbers
Comparing numbers involves determining whether one number is greater than, less than, or equal to another number. This is often done by looking at the place value of the digits starting from the leftmost digit.
Example: Compare 456 and 465.
Starting from the leftmost digit, both numbers have 4 in the hundreds place. Moving to the tens place, 456 has 5 and 465 has 6. Since 6 is greater than 5, 465 is greater than 456.
Rounding Numbers
Rounding numbers involves simplifying a number to the nearest ten, hundred, or thousand. This is useful for estimation and making calculations easier.
Example: Round 378 to the nearest hundred.
The number 378 is between 300 and 400. Since 78 is closer to 100 than to 0, 378 rounds up to 400.
Addition and Subtraction
Addition and subtraction are fundamental operations that involve combining or separating numbers. Understanding these operations helps in solving real-world problems.
Example: Add 234 and 156.
234 + 156 = 390.
Example: Subtract 567 from 789.
789 - 567 = 222.
Multiplication and Division
Multiplication and division are advanced operations that involve repeated addition and grouping, respectively. These operations are essential for more complex calculations.
Example: Multiply 12 by 4.
12 × 4 = 48.
Example: Divide 84 by 7.
84 ÷ 7 = 12.