Understand that expressions represent values, and we can compare them logically without full calculation.
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A rule-of-thumb statement for logical comparisons.
Introduction to arithmetic expressions and their values.
Mallika spends ₹25 every day for lunch at school. How much does she spend in a 5-day week from Monday to Friday? We can write a mathematical phrase for this: .
Worked example showing how to balance expressions.
Find the missing number to make the expressions equal on both sides of the sign:
Faded practice for balancing an expression.
Let's find the missing number to balance the equation: .
Step 1: First, evaluate the arithmetic expression on the right side. .
Step 2: Now we know the left side must equal this same overall value. We ask ourselves, 8 times what gives that number? The missing number is .
Summary of expression equality.
The equals sign signifies an identity in value. It does NOT just mean "the answer is".
For example, we can write , but we can also write because both sides evaluate to 15.
Hook for comparing expressions using logic instead of raw calculation.
Imagine a situation: Raja had 1023 marbles and got 125 more today. Joy had 1022 marbles and got 128 more today. Who has more?
Visualizing Raja and Joy's marbles makes the logical comparison without calculation concrete.
By aligning the starting amounts, we can visually see who gained more overall.