ALEX Classroom Resource

Students:
When given two-digit or three-digit number to round to the nearest 10 or 100,

• Identify the ten or hundreds that the number falls between.
• Plot the number on a number line between the tens or hundreds.
• Identify the nearest ten or hundred and justify the answer.
• Identify a possible value of the unknown number when instructed that an unknown number will round to a given number when rounding to the nearest 10 or 100.

Example: An unknown number will round to 340 when rounded to the nearest 10. Identify a possible value for the unknown number.

Students know:

• Values of the digits in the ones, tens, and hundreds places.
• How to determine what is halfway between two multiples of 10 or 100.
• Strategies for rounding to the nearest 10 or 100.
• Use place value vocabulary and logical reasoning to justify solutions when rounding.

Students are able to:

• Round whole numbers to the nearest 10 or 100.
• Identify a possible value for a number which will result in a given number rounded to the nearest 10 or 100.
  Example: What value will result in 270 when rounded to the nearest 10? Identify the possible values.

Students understand that:

• rounding is determining which ten or hundred a number is closer to.

Learning Objectives:
M.3.10.1: Define rounding.
M.3.10.2: Round whole numbers from 100 to 999 using whole numbers from 10 to 99.
M.3.10.3: Model rounding whole numbers to the nearest 100.
M.3.10.4: Round whole numbers from 10 to 99 using whole numbers from 1 to 9.
M.3.10.5: Model rounding whole numbers to the nearest 10.
M.3.10.6: Identify the steps in rounding two- and three-digit numbers.
Example: Identify the digit that may change and the number to the right.
M.3.10.7: Round whole numbers from 1 to 9 and model to show proficiency.
M.3.10.8: Understand that the two digits of a two-digit number represent amounts of tens and ones.
M.3.10.9: Match the number in the ones, tens, and hundreds position to a pictorial representation or manipulative of the value.