1. Estimation GLE 0506.1.2 Apply and adapt a variety of appropriate strategies to problem solving, including estimation, and reasonableness of the solution. 0506.1.3 Explore different methods of estimation including rounding and truncating.

2. Vocabulary Digits – a number symbol used to make numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) Digits – a number symbol used to make numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) Numbers – Made up of any combination of digits Numbers – Made up of any combination of digits Place Value - The value of a digit based on its position in a number Place Value - The value of a digit based on its position in a number Truncating - To shorten (a number) by dropping one or more digits after the decimal point Whole Number – any positive number that does not have a fractional or decimal part Whole Number – any positive number that does not have a fractional or decimal part

3. Place Value

4. Rounding In order to estimate an answer, we round the numbers in the problem to solve In order to estimate an answer, we round the numbers in the problem to solve Look at each digit in the number. Look at each digit in the number. Determine which place value the digit to be rounded is in. Determine which place value the digit to be rounded is in.

5. Rounding If the digit following that number is five or more, round up. If the digit following that number is five or more, round up. If the digit following that number is four or less, round down. If the digit following that number is four or less, round down.

6. Practice Round to the nearest hundred. Round to the nearest hundred. 234 234 –Since 2 is in the hundreds place, I need to look at the 3 to determine whether to round up or down. What do you think? –Since three is less than 5, I should round down. –200 is the correct answer!

7. Practice Round to the nearest hundred. Round to the nearest hundred. 769 769 –Since 7 is in the hundreds place, I need to look at the 6 to determine whether to round up or down. What do you think? – Since 6 is greater than 5, I should round up. –The correct answer is 800!

8. Practice Round to the nearest hundred. Round to the nearest hundred. 457 457 –Since 4 is in the hundreds place, I need to look at the 5 to determine whether to round up or down. What do you think? –Since 5 is equal to 5, I should round up. –500 is the correct answer!

9. Think You’ve Got It? Try these! 346 346 589 589 947 947 201 201 197 197 300 300 600 600 900 900 200 200

10. Another Way to Look at Rounding Think of a number line. (You may have one in your classroom or on your desk!) Think of a number line. (You may have one in your classroom or on your desk!) As you look at the number you are rounding, think is it closer to the multiple of ten or one hundred below it or above it. As you look at the number you are rounding, think is it closer to the multiple of ten or one hundred below it or above it.

11. Round 7 to the nearest ten. Round 7 to the nearest ten. Look at the number line. Look at the number line. Is 7 closer to 0 or 10? Is 7 closer to 0 or 10? 7 is closer to 10, so we round up to 10. 7 is closer to 10, so we round up to 10.

12. Round 4 to the nearest ten. Round 4 to the nearest ten. Look at the number line. Look at the number line. Is 4 closer to 0 or 10? Is 4 closer to 0 or 10? 4 is closer to 0, so we round down to 0. 4 is closer to 0, so we round down to 0.

13. Truncating We will use We will use truncating when dealing with decimals. If we want to round a decimal number to a whole number, we will need to look at the digit(s) following the decimal point.

14. Truncating Round to the nearest whole number Round to the nearest whole number 23.6 23.6 37.8 37.8 45.2 45.2 61.9 61.9 55.4 55.4 24 24 38 38 45 45 62 62 55 55