Place value in base-10 In the decimal (base-10) numbering system, which digit position is the most significant digit (MSD)?

Introduction / Context:
Positional number systems assign weights to digits based on their position. In base-10, each place to the left is worth ten times the place to its right. The most significant digit (MSD) has the greatest weight and most influence on the numeric value.

Given Data / Assumptions:

• Base-10 positional notation.
• MSD definition sought.
• No leading zeros unless explicitly stated.

Concept / Approach:
The MSD is the leftmost nonzero digit in the integer portion of a number. It contributes the largest magnitude because its positional weight (10^n) is the highest. Conversely, the least significant digit (LSD) is the rightmost digit, weight 10^0 in integers or the smallest fractional weight to the right of the decimal.

Step-by-Step Solution:

Verification / Alternative check:
In 7,254 the MSD is 7 (in the thousands place). Changing the MSD changes the number by thousands, while changing the LSD changes it by ones only, reinforcing the weight concept.

Why Other Options Are Wrong:

• Middle digit/right of decimal/last on the right: These refer to positions but not necessarily the most significant one.

Common Pitfalls:
Confusing MSD with “first typed digit” or misapplying to floating-point notation; always determine significance by position weight, not appearance order alone.

Final Answer:
The digit with the most weight