Mathematical Emphasis
Investigation 1—10’s and Doubles

• Developing familiarity with 10 as an important number in our number system
• Becoming familiar with number combinations of 10 and doubles
• Communicating about mathematical thinking through written and spoken language
• Developing strategies for adding two or more numbers

Investigation 2—Grouping by 2’s, 5’s, and 10’s

• Developing counting strategies
• Exploring patterns and developing fluency in skip counting by 2, 5, and 10
• Exploring 5 and its multiples
• Becoming familiar with the relationship between skip counting and grouping
• Exploring ways of recording and keeping track when counting large groups
• Becoming familiar with coin equivalencies and using money as a model for counting by 5 and 10

Investigation 3—Introducing Addition and Subtraction Situations

• Developing models of addition and subtraction situations
• Solving problems using numerical reasoning
• Recording solution strategies clearly
• Considering the relationship between addition and subtraction
• Working with notation for addition and subtraction

Investigation 4—One Hundred

• Becoming familiar with the structure of 100
• Working with 100 as a quantity
• Using the 100 chart as a tool for combining and comparing quantities
• Using familiar addition combinations to find totals
• Developing strategies to solve addition and subtraction problems

Tips For Helping At Home
Questions To Ask:

• What is the problem about? Tell me in your own words.
• What did you do in class to get started?
• Can you make a drawing (model) to help you figure out the problem?
• What have you already tried? What steps did you take?
• What do you need to do next?
• Can you show it in a different way?
• How did you get your answer?

Activities At Home

• Play the games sent home during the unit including: Tens Go Fish, Turn Over 10, or Close to 20.
• Have your child count handfuls of pennies in different ways (by 2’s, 5’s).
• Ask your child to count the change in your pocket or wallet. Children are working with pennies, nickels and dimes in this unit.
• If you go grocery shopping and use a coupon, ask your child to figure out how much money (in coins) the coupon is worth.

Vocabulary Terms

Doubles

Addition combinations where the addends are the same (2+2, 5+5)

Equation

A mathematical statement containing an equal sign, to show two math expressions are equal

Number Strings

Mathematics problems with more than two numbers being added

Multiple

A mathematical operation where a number is added to itself a number of times

Skip Counting

Counting forward or backward by multiples of a given number

Mathematics Vocabulary Web site

Mathematics Strategy—Learning Addition Combinations
“There are 121 addition combinations from 0+0 to 10+10 and many of these are learned without difficulty. Most students know the combinations that involve +0, +1, and +2, solving these combinations quickly by counting on. They also need to recognize that, for example, 2+8 is the same as adding 8+2, so that they use the more efficient counting-on strategy (8, 9, 10) rather than beginning at 2 and count up 8 more.

Excluding +0, +1, and +2 combinations, there are 36 combinations up to 10+10 if combination pairs are learned together. (It is important to note that not all second graders will see combination pairs, such as 3+7 and 7+3, as the same problem.) These 36 combinations can be grouped to help students learn good strategies for solving them easily.

The Doubles—from 3+3 to 10+10. Students learn most doubles readily and can use the doubles they know to help with the harder doubles. “I know that 6+6 is 12 so 7+7 is 2 more, that’s 14.”

The Near Doubles—3+4, 4+5, 5+6, 6+7, 7+8, 8+9, 9+10. These are 1 away from the doubles. Students can use the doubles they know to learn these. “I know that 5+5 is 10 so 5+6 is 1 more.”

Sums That Make 10—3+7, 4+6, 5+5, 6+4, 7+3. Students need many experiences building all the ways there are to make 10 until they recognize these combinations.

The 10+ Combinations—from 10+3 to 10+10. Because these combinations follow a structural pattern, students learn them readily once they have built them repeatedly with cubes or counted them out on the 100 chart.

The 9+ Combinations—from 9+3 to 9+10. Students can think of these combinations the way: To solve 9+6, take 1 from 6 and add it to the 9 to make 10. The 5 that is left added to the 10 is 15.

Only eight single digit addition combinations do not fall into any of these categories: 5+3, 6+3, 7+4, 7+5, 8+3, 8+4, and 8+6.”

Source: Investigations in Number, Data, and Space: Coins, Coupons, and Combinations. Dale Seymour, 1998. (Pages 30-31)

Mathematics Game—Get to Zero

Materials

Deck of Number Cards 0-10 (four of each)

Student Score Sheet

Counters

Playing the Game

1. Deal five number cards to each player.



2. Players will use three cards to try and make the sum of 20. The goal is to get as close to 20 as possible. The player’s score is the difference between 20 and his/her sum.



3. Take turns using three cards to try to make 20.



4. To find the score for each turn, write these numbers and the total on the student score sheet. The score for the round is the difference between the total and 20. (8+7+3=18 and 20-18=2 so the score is 2.)



5. Put the used cards in a discard pile and deal out three new cards to each player. If a player runs out of cards before the end of the game, shuffle the discard pile and use them again.



6. After five rounds, total the scores. The player with the lowest score is the winner.

Get to Number Cards (for printing)

Get to Score Sheet (for printing)