CHAPTER 1                            LESSON 1

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“PLACE VALUE AND ROUNDING NUMBERS”

Problem:  Show the places and values of the digits of a number.

 PLACES Millions Hundred- thousands Ten- Thousands Thousands Hundreds Tens Units or Ones . tenths hundredths thousandths DIGITS 4, 1 5 2, 9 0 7 . 8 6 3 VALUES 4,000,000 100,000 50,000 2000 900 NO TENS 7 . 8 10 or 0.8 6 100 or 0.06 3 1000 or 0.003

Examples:

30.47

 Digit Place Value 1.   3 ?? ?? 2.   0 ?? ?? 3.  ?? tenths ?? 4.   ?? ?? 7  100

30.47

 Digit Place Value 1.   3 tens 30 2.   0 units or     ones 0 3.   4 tenths 0.4 or 4              10 4.   7 hundredths 7  100

ROUNDING WHOLE NUMBERS AND DECIMALS

The most common method for rounding WHOLE NUMBERS consists of the following steps:

• 1. Locate the digit in that place.
• 2. Consider the digit to the right.
• If this digit is 5 or more, then round up.
• If this digit is 4 or less, then round down.
• 3. Change all digits to the right of the rounding place to zeros.

Example:

Round 8467 to nearest hundred.

1.  The digit in the hundreds place in the number 8467 is 4

2.  Check the digit to the right of the 4.  What number is to the right of the 4??  Answer: 6.    6 is more than 5 so we will round up.

3.  We need to add a 1 to the 4 which was in the hundreds place—so the answer becomes 8500 since we are rounding off.

To round off decimals:

Find the place value you want (the "rounding digit") and look at the digit just to the right of it.

If that digit is less than 5, do not change the rounding digit but drop all digits to the right of it.

If that digit is greater than or equal to five, add one to the rounding digit and drop all digits to the right of it.

Example:

Round 0.628 to nearest tenth.

1.  Find the digit that is in the tenths place.  In the problem 0.628—the 6 is in the tenths place.

2.  Look at the digit that is to the right of the 6—that would be 2.  Since 2 is less than 5, we would not change the number in the tenths place—just drop the numbers after the 6, since we are rounding off to the nearest tenth.

Final Example:

Round 326,735 to the nearest thousand.

Follow the rules above for rounding whole numbers.

1.  Determine what digit is in the thousands place??  In the number 326,735--the number in the thousands place is 6.  Look to the number to the right of the 6.  That number is 7.  7 is more than 5, so we will add a 1 to the number 6, which changes the number to 327,000 since the final numbers are changed to zeros since we are rounding off.  The answer is 327,000

Work on the problems below.  You will see boxes below.  After working on your problems, you are to type the correct answer into the selected boxes and then submit only those answers. Your other answers can be checked by clicking onto “CHECK ANSWERS.”

Round each number to the place shown.

 To the nearest hundred: 1.  6324 2.  8761 3.  71,583 4.  69, 208 To the nearest thousand: 5.  4294 6.  5026 7.  39,057 8.  79,637 To the nearest tenth: 9.  0.12 10.  0.46 11.  6.021 12.  4.903 13.  2.695 To the nearest hundredth: 14.  0.392 15.  0.018 16.  35.613 17.  98.765 18.  3.166 19.  48.019

Student’s First & Last Name:

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