In this unit, the fourth of four second grade units focused on addition and subtraction, students solve comparison story problems, develop fluency with subtraction within 100, and use representations to model and solve addition and subtraction problems about 3-digit numbers. They also achieve fluency with telling time to the nearest five minutes and should be fluent with the addition and subtraction facts they have been working on throughout the year.
Spend $1.00 We have been playing Spend $1.00 at school. Children take turns rolling dice and then subtracting that amount (in cents) from one dollar. You can play this at home, or just pose problems about subtracting an amount from one dollar. Use coins to help your child think about how much money he or she would have left.
Solving Addition and Subtraction Problems Look for 2-digit and 3-digit addition and subtraction situations at home, such as the following:
There are 36 blueberries in one container and 28 strawberries in another container. How many berries do we have?
If you have 250 pennies in your piggy bank and you give 120 to your friend, how many pennies do you have left?
Have a pencil and paper available, and ask your child to explain how he or she is solving the problems. Encourage your child to make up problems for you to solve.
Cover Up Students are working on a new set of subtraction facts. Play Cover Up with your child to practice these facts.
Begin with some pennies (between 11 and 18). First ask your child to figure out how many pennies there are. When your child is not looking, cover up some of the pennies. Then, ask your child how many pennies he or she thinks are under the paper. For example, start with 11 pennies and cover up 5.
Encourage your child to think about how many pennies are showing, and what combination would make 11. Encourage them to think about and use facts they know to help them(e.g., “Ho w could knowing that 5 + 5 = 10 help?”).
Math and Literature
Burns, Marilyn. The $1.00 Word Riddle Book.
Hulme, Joy N. Sea Sums.
Nolan, Helen. How Much, How Many, How Far, How
Heavy, How Long, How Tall Is 1000?
Robinson, Elizabeth K. Making Cents.