Mathematical Emphasis
Investigation 1—Number Combinations

• Finding combinations of numbers up to about 20
• Finding the total of two or more single-digit numbers
• Exploring relationships among different combinations of a number

Investigation 2—Twos, Fives, and Tens

• Developing strategies for organizing sets of objects so that they are easy to count and combine
• Finding the total of several 2’s, 4’s, 5’s, or 10’s
• Recording strategies for counting and combining, using pictures, numbers and words
• Reading, writing, and sequencing numbers to 100
• Becoming familiar with coins and equivalencies among them

Investigation 3—Addition and Subtraction

• Visualizing combining and separating problem situations
• Developing strategies for solving combining and separating story problems
• Recording strategies for solving combining and separating story problems using pictures, numbers, words, and equations

Tips For Helping At Home
Questions To Ask:

• What is the problem about? Tell me in your own words.
• What did your teacher show you in class?
• Can you make a drawing (model) to show that?
• What have you done so far?
• What do you need to do next?
• Can you show it in a different way?
• How did you get your answer?

Helping At Home

• Your child will bring home some of the math games being played at school with number cards, dot cards, coins, and counters. Take time to learn and play these games with your child.
• Look for opportunities to count large groups of objects. You might ask your child to count a handful of pennies, marbles, or paper clips. If several people take handfuls, count each one and have your child compare them to find which is larger.
• Look for addition and subtraction situations at home. (Numbers under 25 are about right for many first graders.) For example: If you have 20 cents and spend 15 cents, how many cents do you have left?

Vocabulary Terms

Addition

The mathematical term for combining problems

Coins

Children will use pennies, nickels, dimes, and quarters in this unit

Combinations

Ways of grouping objects and/or numbers together

Combining

Putting groups together

Dot Cards

Number cards using dots in common patterns like on dice and dominoes

Equation

A mathematical statement containing an equal sign, showing two expressions are equal

Separating

Breaking apart groups into smaller groups or sets

Skip Counting

Counting up by multiples of a number (2, 4, 6, 8….)

Strategy

A method for solving a problem

Subtraction

The mathematical term for separating problems or finding the difference between two groups

Mathematics Vocabulary Web site

Mathematics Strategy—Building on Number Combinations You Know

In first grade children are just becoming familiar with addition combinations from 0 + 0 to 10 + 10. As they work with numbers in many different ways, first graders begin to reason about the combinations they already know and use these to figure out others.

Counting On from a Known Combination. Counting on is a strategy where children count up from a number combination they know. In solving a combination like 3 + 5, a child may begin with a known combination like 3 + 3 and count up two more from the total of 6 to reach 8.

Counting Back from a Known Combination. Counting back to find a new number combination is less commonly used by first graders. A child could reason that 3 + 5 can be reached by counting back from 5 + 5 by two for a total of 8. Counting backwards, or taking away, is less familiar to first graders than counting up and building numbers by combining parts.

Breaking a Familiar Combination into Parts and Recombining the Parts. Another way to find a new combination, is by breaking numbers being combined into parts that are easy to combine. When adding 8 + 7, a child might know that 8 is 5 + 3 and the 3 can be added to the 7 to make a ten. This would give a total of 15. Students using this strategy recognize that the total remains the same regardless of the order in which the numbers are combined.

Adjusting the Numbers in a Familiar Combination. Some first graders begin to realize that if they add an amount to one number in a combination and take away that same amount from another, the total remains the same. In combining 4 + 9, a child might add 1 to the 9 (10) and take 1 away from the 4 (3) for a total of 13.

First graders will use many of the above strategies in their number work this year. All of the examples are strategies that lead to more efficient work with number combinations.

Source: Investigations in Number, Data, and Space: Number Games and Story Problems. Dale Seymour, 1998. (Pages 22 and 23)

Mathematics Game—Fish for Tens

A mathematics card game based on the traditional game of “Go Fish.”

Materials

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

Players: 2 to 4

Playing the Game

1. The object of the game is to get pairs of cards that total 10. Each player is dealt five cards and the rest are placed face down in the center as a draw pile.



2. If players have any pairs of cards that total 10, they are placed in front of that player and those cards are replaced with cards from the deck.



3. The person to the dealer’s left starts and asks one other player for a card that will go with a card in his/her hand to make 10.



4. If that player gets the card, the pair of cards is put down and one new card is drawn from the deck. This turn is over.



5. If that player did not get the card to make a ten, he/she takes the top card from the deck and that turn is over.



6. If the card drawn from the deck makes 10, the pair is put down, another card is drawn and that turn is over.



7. If a player runs out of cards but there are still cards in the deck, that player draws two more cards.



8. The game is over when there are no more cards left. The person with the most pairs wins.

Get to Number Cards (for printing)