NCERT Solutions Class 7 Maths Chapter 2 — Arithmetic Expressions

Solution:

Step 1: The order of operations (BODMAS) provides a standard rule set for performing calculations.

Step 2: Following this specific order ensures that everyone evaluates an expression in the same way, thus leading to one unique and correct result, preventing ambiguity.

Solution:

Step 1: First, perform multiplication and division from left to right: 6 × 2 = 12 and 10 ÷ 5 = 2.

Step 2: The expression becomes: 15 + 12 - 2.

Step 3: Next, perform addition and subtraction from left to right: 15 + 12 = 27.

Step 4: Finally, 27 - 2 = 25.

Solution:

Step 1: According to the BODMAS rule, multiplication (M) should be performed before subtraction (S).

Step 2: Ravi incorrectly performed subtraction (20 - 5) first.

Step 3: The correct first step should have been 5 × 3 = 15, then 20 - 15 = 5.

Solution:

Step 1: First, solve the operation inside the brackets: 12 - 4 = 8.

Step 2: The expression now becomes: 8 × 8 ÷ 2.

Step 3: Next, perform multiplication and division from left to right: 8 × 8 = 64.

Step 4: Finally, perform the remaining division: 64 ÷ 2 = 32.

Solution:

Step 1: According to BODMAS, 'B' stands for Brackets.

Step 2: Brackets are used to group parts of an expression, indicating that the operations within them must be performed before any operations outside, effectively overriding the standard order of operations.