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NCERT · Ganita Prakash · Volume 1 · Chapter 4
Expressions using Letter-Numbers
9 videos in this chapter
Letters representing numbers
2 videos
Chapter 4
How Can a Letter Stand for a Changing or Unknown Number?
3:04
How Can a Letter Stand for a Changing or Unknown Number?
You'll learn: A letter can stand for a quantity that changes or for one we don't know yet.
Chapter 4
Describe a Number Relationship with Letters
3:10
Describe a Number Relationship with Letters
You'll learn: Translate a number relationship described in words into an expression with letters.
Formulas from quantities
3 videos
Chapter 4
Write a Formula for a Total Cost
3:09
Write a Formula for a Total Cost
You'll learn: Write a formula for total cost as price times quantity.
Chapter 4
Express an Age Relationship with a Letter
3:04
Express an Age Relationship with a Letter
You'll learn: Write one person's age in terms of another's using a letter.
Chapter 4
Write Perimeter Formulas for Regular Shapes
3:09
Write Perimeter Formulas for Regular Shapes
Calendar and number-grid relationships
2 videos
Chapter 4
Write Relative Values in a Calendar or Number Grid
3:03
Write Relative Values in a Calendar or Number Grid
You'll learn: Write every cell of a calendar or grid block relative to one cell, using row and column rules.
Chapter 4
Why Do the Diagonal Sums Match in a Number Grid?
3:17
Why Do the Diagonal Sums Match in a Number Grid?
You'll learn: Using a letter for one corner shows both diagonal sums are always equal.
Evaluating algebraic expressions
2 videos
Chapter 4
Substitute a Number Without Changing the Expression's Structure
3:03
Substitute a Number Without Changing the Expression's Structure
You'll learn: Replace the letter with a number but keep every operation of the expression unchanged.
Chapter 4
How Does an Expression's Value Change with Its Input?
3:17
How Does an Expression's Value Change with Its Input?
You'll learn: Substitute different inputs to see how the value of an expression changes.
You'll learn: The perimeter of a regular shape is the number of sides times the side length.