NCERT Exemplar Solutions
Class 6 - Mathematics - Unit 1: Number System - Multiple Choice QuestionsQuestion 15
Class 6 - Mathematics - Unit 1: Number System - Multiple Choice Questions
Question. 15
The product of the successor and predecessor of 999 is
(A)
999000
(B)
998000
(C)
989000
(D)
1998
Detailed Answer with Explanation:
Step 1: Find the successor of 999.
Successor means the next number: \(999 + 1 = 1000\).
Step 2: Find the predecessor of 999.
Predecessor means the previous number: \(999 - 1 = 998\).
Step 3: Multiply the two numbers.
We need \(1000 \times 998\).
Easy place-value method:
\(998 \times 1000\) just adds three zeros: \(998000\).
Or, using distributive property:
\(1000 \times 998 = 1000 \times (1000 - 2)\)
\(= 1000 \times 1000 - 1000 \times 2\)
\(= 1000000 - 2000\)
\(= 998000\).
Answer: \(998000\) → Option B.