Round whole numbers and decimals: find the missing digit

Learning Objectives Identify the place value to which a number is being rounded. Apply standard rounding rules to both whole numbers and decimals. Determine the possible range of an original number given its rounded value. Work backward from a rounded number to find a single missing digit in the original number. Identify all possible values for a missing digit that satisfy a given rounding condition. Explain the reasoning behind their choices for missing digits in rounding problems. Ever wondered how a price like $19.99 can feel like $20, or how a population estimate of 300,000 is derived? 🤔 It's all about rounding! In this lesson, we'll dive into the rules of rounding whole numbers and decimals. More importantly, we'll learn how to use these rules in revers...

TermDefinitionExample Place ValueThe position of a digit in a number that determines its value. For example, in 345, the '4' is in the tens place, meaning it represents 40.In the number 123.456, the digit '2' is in the tens place, and the digit '5' is in the hundredths place. Rounding DigitThe digit in the specific place value to which you are rounding. This is the digit that might change.To round 4.73 to the nearest tenth, the '7' is the rounding digit. Look-to DigitThe digit immediately to the right of the rounding digit. This digit determines whether the rounding digit stays the same or rounds up.To round 4.73 to the nearest tenth, the '3' is the look-to digit. Rounding UpWhen the look-to digit is 5 or greater (5, 6, 7, 8, 9), the round...

General Rounding Rule 1. Identify the rounding digit (the digit in the place value you're rounding to). 2. Look at the digit immediately to its right (the look-to digit). 3. If the look-to digit is 5 or greater ($\ge 5$), round the rounding digit UP by adding 1 to it. 4. If the look-to digit is less than 5 ($< 5$), keep the rounding digit the SAME. 5. All digits to the right of the rounding digit become zero (for whole numbers) or are dropped (for decimals). This is the fundamental rule for rounding any number, whether whole or decimal. It dictates how the rounding digit changes based on the digit next to it. Finding Missing Digits (Working Backward) To find a missing digit, consider two scenarios based on the rounding rule: 1. If the rounded number is *higher* than t...