Dear Parents:
If you watch your second grader working with numbers, you will probably notice that math education
has changed dramatically from when you were in elementary school! Arithmetic is no longer about
teaching children to memorize the traditional algorithms (i.e. lining up the numbers and then
"carrying" or "borrowing"). It is about building children's "number sense" and their ability to
manipulate numbers. Once children have this understanding, the traditional algorithms make sense
to them. However, the traditional algorithm is often NOT the most efficient strategy!
For example:
1. If you want to add $7.95 and $2.95 to order Scholastic Books, you might think: $8 + $3 = $11.
$11.00 � two nickels = $10.90. This method is more efficient than writing out the traditional
algorithm or using a calculator.
2. In order to subtract 18 from 44, you might think: 44 � 20 + 2 = 26.
3. In order to add 37 and 28, you might think: 37 + 30 - 2 = 65.
In class this year, one tool children will learn is to draw a quick number line in order to solve addition
and subtraction problems in this way. When they want to add a series of numbers together, they are
encouraged to make the easiest combinations first (i.e. "combinations to ten" and "doubles").
RIGHT NOW IN MATH WORKSHOP, WE ARE WORKING ON A UNIT CALLED "COINS, COUPONS, AND
COMBINATIONS." In this unit, your child is learning about how numbers are made from other
numbers- 20 can be made from 10 and 10 or from four 5�s or from ten 2�s. Being able to take
numbers apart and put them back together flexibly is the basis for developing good number sense.
In the first half of this unit, we worked with addition combinations, exploring combinations of 10 (4
+6, 2+8, 7+3) and doubles (3+3, 7+7, 9+9). We used these addition combinations to learn others.
The goal for the children is to become familiar with number combinations through repeated use and
by learning about relationships between numbers.
In the second half of this unit, your child is working with numbers such as 5, 10, 15, 20, 25, 50, and
100. Activities include using coins to find different ways to make 25 cents and figuring out how to
save 50 cents at the grocery store using combinations of coupons. Students are also working on
story problems that they need to solve with addition or subtraction.
WHILE OUR CLASS IS WORKING ON THIS UNIT, YOU CAN HELP YOUR CHILD IN SEVERAL WAYS:
� Continue to play "Tens Go Fish," "Turn Over 10," and "Close to 20" with your child at home. The
more your child can practice combinations to ten and twenty, the more automatic these
combinations will become. Some families have found it fun to schedule a Family Game Night each
week.
� Ask your child to take a handful of small objects like buttons, pretzels, marbles, etc. Then have
your child count the number of objects. In school students are encouraged to check their count by
counting a second time in a different way (by 2�s and 5�s). Your child might compare his or her
handful of objects to your handful.
� You might give your child a small collection of coins to count over breakfast. He/she might find it
helpful to place the coins on the hundred chart to add them up.
� Give your child opportunities to count out coins in real life situations (i.e. to buy something very
small at a store). Ask your child to figure out ahead of time how much change he/she should receive
in return.
� Practice counting backward by 1�s, 2�s or 5�s from specific numbers up to 100. For an extra
challenge, try counting skip counting by 3�s, 4�s, and 6�s.
