The Mathematics of Planet Earth 2013 Collection is now available. COMMON CORE

Make the Connection


Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each.

Divide your class into small groups. Give each group a container of math links. Present a repeated addition problem, such as 3 + 3 + 3, and have students model the problem using the links. Ask a group to share their model with the class and reveal the answer. Then share that their answer is also the answer to the multiplication problem 3 x 3. Explain that the multiplication sign can be read as groups of and—since they made three groups, or links, of three—they modeled the multiplication problem too. Present other repeated addition problems for the groups to model and have them name the answers and the corresponding multiplication problems.

Off the Charts!

Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes.
Estimate lengths using units of inches, feet, centimeters, and meters.
Challenge students to race against the clock as they play this fast-paced game. On the board, draw and label two two-column charts with the headers shown. Assign one chart to each team. Give the first player on each team a marker. Name an object in the classroom and ask the first players to estimate the length of the object. Reveal the actual measurements and award one point for the estimate that is closest to the actual measurement for each object.To vary the game, use different units of measure such as ounces, pounds; minutes, hours; or cups, quarts.
In the Cards

Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and < symbols to record the results of the comparisons.
Are you ready to deal out some number-sense fun? First, make a supply of inequality cards. Next, remove the face cards and tens from a deck of cards. Give each student a playing card and a copy of the "Number Sense Fun" activity sheet. Organize students into groups of six to make two three-digit numbers. Deal one inequality card to each group. Instruct students in each group to organize their cards to make a true expression. Then, in turn, invite them to write their numbers and expression on the white board. Confirm that the expression is accurate; then direct each student to copy the numbers and expression onto his paper. After each group has shared, challenge each student to write a second true expression for each set of numbers.

Sammy's Sports Complex


Relate area to the operations of multiplication and division.

Shape up students' skills for finding area! Give each student a copy of the "Sammy's Sports Complex" activity sheet to complete. If desired, have students check their work by applying the formula for area (length × width).
Don’t Forget the Bows!


Draw a picture graph (with single-unit scale) to represent a data set with up to four categories. Solve simple put-together, take-apart, and compare problems using information presented in a bar graph.

Materials needed:• varying numbers of 2"–3" red, green, blue, and yellow bows (fewer than 9 of each color)• a large recycled gift bag• a large paper grid (similar to the grid on “Don't Forget the Bows!”)• a class supply of “Don’t Forget the Bows!”• crayons
Setting up the center:1. Store the bows in the gift bag and put it at a center. Place the grid on the floor nearby.2. Display the forms and crayons at the center.
Using the center:1. A student removes the bows from the bag and sorts them by color.2. She places each bow on the large paper grid.3. She records her results on a copy of “Don’t Forget the Bows!” and completes the activity.

Starting Small


Use place-value understanding to round whole numbers to the nearest 10 or 100.

To begin, show students an unopened bag of mini marshmallows and challenge them to guess how many are in the bag. Record their responses on the board; then give each student a sample of marshmallows and a copy of a mug pattern. Instruct each child to cut out the pattern, count her marshmallows, and write the number on the mug as shown. Next, divide students into small groups. Guide each child to round her total to the nearest ten and then write all her group’s rounded numbers on the mug. Direct students to add the rounded numbers to find an estimate for their group. After each group shares its estimate, use the data to calculate a class estimate. Lead students to understand that determining a small estimate can help them find a larger one.

Pattern Play


Count within 1,000; skip-count by 5s, 10s, and 100s.

This one-on-one activity helps students review skip-counting and number patterns. Cut out a copy of the number cards and place each set in a plastic bag. Have a student arrange the cards from one set in numerical order. Then direct the student to turn away while you remove a few cards from the series. Refocus the child on the cards and have him identify the missing numbers by skip-counting the number sequences. As an alternative, use the review as a partner activity.
Rolled Into One
Apply properties of operations as strategies to multiply and divide.
To complete this activity, each group of three needs three dice and a calculator. Direct each student to roll a die; then have the students use the numbers rolled to make and solve as many multiplication sentences as they can. After a few rounds, have groups review their results and identify any patterns that occur. Then lead students to an understanding that the order of the factors doesn’t matter—the same multiples always equal the same product.

Hooray for Hand-Me-Downs!
Addition to 100, word problems involving money

Spring Garden


Determine whether a group of objects (up to 20) has an odd or even number of members.

Materials needed:• a sanitized egg carton• scissors• a permanent marker• 12 construction paper flowers, each glued to a different craft stickSetting up the center:1. Turn the egg carton upside down. Use scissors to make a small slit in each cup bottom.2. Label the cups in one row “even” and the cups in the other row “odd” as shown.3. Program the centers of six flowers with different even numbers and the centers of the other six flowers with different odd numbers.4. For self-checking, write “e” or “o” on the back of each flower.5. Display the carton and the flowers at a center.Using the center:1. A student selects a flower and determines if the number on it is even or odd.2. She inserts the flower in the correct row of the carton.3. After placing all the flowers, she checks her work by looking at the back of each flower.

In Formation


Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measurement quantities, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

To begin, instruct each child to cut apart the ant cards. Sing the song “The Ants Go Marching” and then revisit the second verse. Direct students to move their ant cutouts to show them paired in groups of two. Discuss the number of pairs and how this relates to equal sharing and division. Repeat with the third, fourth, sixth, and eighth verses, instructing students to manipulate their ants accordingly. Sing the fifth, seventh, and/or ninth verses to introduce remainders, having students group the ants and guiding them to understand that the ungrouped ants are known as remainders. To extend the activity, have each child write on a sheet of 11" x 17" paper an equal-sharing word problem about the ants. Then have him glue the ants to his paper to show the answer.

Right on Target


Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.

Toss your students some math practice with this activity for two. Use a permanent marker to label the fronts and backs of each of eleven beanbags with different numbers from zero to ten. Place the beanbags and a calculator in a bucket and place a hula hoop (target) a short distance away on the floor. Player 1 stands at the bucket while Player 2 stands at the target. Player 1 takes two beanbags from the bucket and tosses them into the target. Player 2 reads the numbers and uses them to say and solve a math fact; then Player 1 checks the problem on the calculator. If a beanbag doesn’t make it in the target, Player 2 looks at the numbers on that beanbag and chooses one to use in his math fact. Students continue until one beanbag remains in the bucket; then they switch places.

Rain, Rain, Go Away!


Draw a bar graph (with single-unit scale) to represent a data set with up to four categories. Solve simple put-together, take-apart, and compare problems using information presented in a bar graph.


• copy of the cloud patterns, cut out

• envelope, labeled as shown

• graph paper

• crayons

Place the clouds in the envelope; then set out the envelope with the graph paper and crayons. A student takes four clouds from the envelope and graphs the data on his paper. Then he turns the paper over and writes four or more questions about the data. If desired, have the student include the answers.