# Rounding Whole Numbers

## Presentation on theme: "Rounding Whole Numbers"â€” Presentation transcript:

Rounding Whole Numbers
EnVision Math Topic 1: Lesson 1-4 Rounding Whole Numbers Materials needed: -dry erase board, marker, eraser for each student -large yellow card and large green card for each student and a marker and a way to attach them to the board -number line from slide 9 drawn on board (or just project on board) yellow cards with the numbers 306, 311, 323, 335, 342 on them in case these tens digits are not written by students -green cards with the numbers 351, 362, 374, 385, 397 on them -rounding game cards, gameboard, playing pieces, and die for each pair of students

â€¦practice sheet for today.
Write your name * on the name line. Look * to see which level you are starting with today. Then find yourâ€¦

â€¦Rocket sheet. Down at the bottom * find the level you are on today. If it is the same level as last time, write your date under the next try. If you passed last time , then you are on a new level today. You may color in the letter that you passed on your rocket. Then you will fill in the date under first try for your new level. Remember, these are our partners for the weekâ€¦

Rocket Math Partners Luka and Issy Mason and Jack
Ellie and Sierra Gabe and Wes Samantha and Alyssa Dominic and Jace Emily and Paige Anthony and Oluwafolajinmi When I say go, find your partner and choose a spot. Decide who will be the checker first and get your answer sheet ready. I will give you the signal when you should start practicing. Then I will give you the signal when to switch. Go! (after practice â€“ do one minute timing) Today we have a new big questionâ€¦

How do I round numbers? Can someone read it?
You have used place value to read and write numbers. Today, you will use place value to round numbers. When might you want to round numbers? (when you only need to estimate, to check if an answer makes sense) Using what you learned about rounding from last year, here is what I would like you to doâ€¦

Write a number that is greater than 300 that rounds to 300.
400 I am going to give you and your partner a yellow card and a green card. On the yellow card, I would like you toâ€¦* On the green card, I would like you toâ€¦* When you are finished, I would like you to put your card in the correct column on the board. (while kids work, make sure you have the number line drawn on the board â€“ have yellow cards with the numbers 306, 311, 323, 335, 342 on them in case these tens digits are not written by students â€“ have green cards with the numbers 351, 362, 374, 385, 397 on them) Letâ€™s look at our yellow cards. Are there any that you disagree with? Each of these numbers when rounded to the nearest hundred equals What place do you look at if you are rounding to the nearest hundred? (tens) Let me circle all the tens digits. (do) What do you notice? (all less than 5) (do the same for the green cards) Based on what we just found out, letâ€™s make some rules for rounding numbersâ€¦ Write a number that is greater than 300 that rounds to 300. Write a number that is greater than 300 that rounds to 400.

8,723 9 ,000 Round to the nearest thousand.
Suppose I wanted to round this number to the nearest thousand. Here is the first thing I would need to doâ€¦* I want to underline that place. What digit is in the thousands place? * Here is step 2 *. It is helpful to draw * an arrow to the digit to the right. Letâ€™s look again at our numbers on the board. If the digit in the tens place was 5 or more, what happened to our digit in the hundreds place? (had to make it one more â€“ 4) If the digit in the tens place was less than 5, what happened to our digit in the hundreds place? (stayed the same) So, we need to rememberâ€¦* * Is our digit to the right 5 or more or less than 5? What do I do to my thousands digit? * (make it one more) What happens to all these other digits? * (0â€™s) Since I am rounding to the nearest thousand and one thousand has 3 zeroes, my answer should have 3 zeroes. 9 ,000 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

293,685,407 293,68 5 ,000 Round to the nearest thousand.
Now letâ€™s try our rules with a bigger number. Suppose I wanted to round this number to the nearest thousand. First I need toâ€¦*. What should I underline? * Next I need toâ€¦* What should I draw an arrow to? * Rememberâ€¦* * What will I do to my 5? * (keep it the same) What do I change the digits behind the 5 to? * (0â€™s) What happens to all the digits in front of the 5? * (stay the same) Since I was rounding to the nearest thousand, I should have 3 zeroes in my answer. 293,68 5 ,000 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

293,685,407 293, 7 00,000 Round to the nearest hundred thousand.
This time, letâ€™s round our number to the nearest hundred thousand. What should I underline? * What should I draw an arrow to? * What will I do to my 6? * What do I change the digits behind the 6 to? * What happens to all the digits in front of the 6? * Since I was rounding to the nearest hundred thousand, I should have 5 zeroes in my answer. 293, 7 00,000 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

293,685,407 293,685, 4 00 Round to the nearest hundred.
This time, letâ€™s round our number to the nearest hundred. What should I underline? * What should I draw an arrow to? * What will I do to my 4? * What do I change the digits behind the 4 to? * What happens to all the digits in front of the 4? * Since I was rounding to the nearest hundred, I should have 2 zeroes in my answer. 293,685, 4 00 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

293,685,407 29 4 ,000,000 Round to the nearest million.
This time, letâ€™s round our number to the nearest million. What should I underline? * What should I draw an arrow to? * What will I do to my 3? * What do I change the digits behind the 3 to? * What happens to all the digits in front of the 3? * Since I was rounding to the nearest million, I should have 6 zeroes in my answer. 29 4 ,000,000 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

293,685,407 293,6 9 0,000 Round to the nearest ten thousand.
This time, letâ€™s round our number to the nearest ten thousand. What should I underline? * What should I draw an arrow to? * What will I do to my 8? * What do I change the digits behind the 8 to? * What happens to all the digits in front of the 8? * Since I was rounding to the nearest ten thousand, I should have 4 zeroes in my answer. 293,6 9 0,000 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

293,685,407 293,685,4 1 Round to the nearest ten.
This time, letâ€™s round our number to the nearest ten. What should I underline? * What should I draw an arrow to? * What will I do to my 0? * What do I change the digits behind the 0 to? * What happens to all the digits in front of the 0? * Since I was rounding to the nearest hundred thousand, I should have 1 zero in my answer. Now itâ€™s your turn to try some. Weâ€™ll use our white boards. (pass out boards, markers, erasers) 293,685,4 1 Find the place that I am rounding to. Look at the digit to the right of this place. If the digit to the right is or more, add 1. If the digit to the right is less than 5, leave it alone.

Round to the place of the underlined digit.
128,955 I would like you to round this number to the underlined digit. On your board, write this number and draw your underline. Then draw your arrow and write your rounded number below this number. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 12 9 ,000

Round to the place of the underlined digit.
85,639 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 85,6 4

Round to the place of the underlined digit.
9,924 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 10 ,000

Round to the place of the underlined digit.
1,194,542 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 9 1,1 0,000

Round to the place of the underlined digit.
160,656 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 2 00,000

Round to the place of the underlined digit.
493,295 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 49 3 ,000

Round to the place of the underlined digit.
39,230 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 3 9 ,000

Round to the place of the underlined digit.
77,282 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. Here is your next oneâ€¦ 77,2 8

Round to the place of the underlined digit.
54,846 I would like you to round this number to the underlined digit. Show me your answer! I had to look at the digit to the right * Since it wasâ€¦, my underlined digit became *. Everything behind it, became * zeroes. Everything in front of it, stayed * the same. You can also round money amounts. This is especially useful when you are at the store and trying to see if you have enough money. 5 0,000

Round to the nearest dollar.
\$6.73 I want to round this money amount to the nearest dollar. What digit is in the dollar place? * I still look to the right *. What happens to my 6? * What happens to everything behind the 6? * What am I missing? * \$ 7 .00

Round to the nearest dollar.
\$254.13 Letâ€™s round this money amount to the nearest dollar. What digit is in the dollar place? * To the right *, there is a 1. What happens to my 4? * What happens to everything behind the 4? * Everything before the 4 * stays the same. \$25 .00 4

Round to the nearest dollar.
\$92.87 Letâ€™s round this money amount to the nearest dollar. What digit is in the dollar place? * To the right *, there is an 8. What happens to my 2? * What happens to everything behind the 2? * Everything before the 2 * stays the same. Now itâ€™s your turn. \$9 .00 3

Round to the nearest dollar.
\$537.27 Round this money amount to the nearest dollar. Here is the dollar place. * I look to the right. * My 7 * stays the same. Everything behind it becomes * 0. Everything before it * stays the same. \$53 .00 7

Round to the nearest dollar.
Round this one to the nearest dollar. Here is the dollar place. * I look to the right. * My 8 * becomes a 9. Everything behind it becomes * 0. I can also round money amounts to the nearestâ€¦ \$38.95 \$3 .00 9

Round to the nearest ten dollars.
\$57.25 â€¦ten dollars. In the ten dollar place, I have aâ€¦* To the right *, there is a 7. What happens to my 5? * What happens to everything behind the 5? * \$6 .00

Round to the nearest ten dollars.
\$32.99 Round this one to the nearest ten dollars. What digit is in the dollar place? * To the right *, there is a 2. What happens to my 3? * What happens to everything behind the 3? * \$3 .00

Round to the nearest ten dollars.
\$91.88 Round this money amount to the nearest ten dollars. Here is the ten dollar place. * I look to the right. * My 9 * stays the same. Everything behind it becomes * 0. \$9 .00

Round to the nearest ten dollars.
Round this money amount to the nearest ten dollars. Here is the ten dollar place. * I look to the right. * My 7 becomes...* Everything behind it becomes * 0. To do a little more practice, you are going to play a game with a partner. You and your partner will have a bag of cards. When it is your turn, reach in and pull out a card. Both people should write their answer on the board. When finished, check the answer on the back of the card. If you are correct, you may roll the die. If not, figure out your mistake. Continue playing until someone wins or time runs out. \$78.15 \$8 .00