Boosting Number Sense
Memorization and practice will help your child hone basic skills.
Second grade is traditionally thought of as a review year. The weighty academic subjects of reading, addition, and subtraction taught in 1st grade need to be mastered in second. So while 2nd grade teachers still use fun, hands-on tools and games to reinforce math concepts, you can expect more worksheets, homework, and tests.
Fortunately, the first month or two is generally devoted to reviewing addition and subtraction — a lot of knowledge gets lost over the summer. Teachers won’t attempt to start double-and triple-digit subtraction until all the kids in the class are again fluent in their math facts.
Counting Short Cuts
Mental Math
Adding On
Counting Short Cuts
Part of each day is typically spent with computation practice. Teachers may have kids “compete” against themselves by completing addition and subtraction worksheets. At my daughter’s school, 2nd graders work through successive levels of addition and subtraction fact sheets at their own pace. Once they complete a page without any errors, they put a sticker on their chart and move up to the next level. This individual approach also helps the teacher assess which children may need extra help.
Timing of math tests and worksheets may also begin in 2nd grade. Some teachers feel that timing is necessary to push kids to memorize math facts and know the answers instinctively. Others take a dimmer view. “Timed tests are not the best way to know if students can compute well, and often have negative consequences,” says Cathy Seeley, president of the National Council of Teachers of Mathematics, based in Reston, Virginia. “The speed, pressure, and overwhelmingness of it can be the beginning of math phobia.” A better approach, she says, and one that many teachers use, is to help kids understand the nature of addition and subtraction and give them tools for reaching sums and differences quickly in their heads. Research shows that having good number sense, and being able to recognize combinations and do calculations mentally, is vital to proficiency in math. “Number sense is critical,” says Ms. Seeley. “If done well, it serves children throughout their lives.”
For example, when teaching students how to add 26 plus 32, second grade teachers may show kids how they can break the 26 into 20 plus 6, and the 32 into 30 plus 2. Then they can add the tens together, to get 50, and the ones to get 8, to come up with the correct answer of 58. Not only can children do such calculations more easily in their heads, but breaking the numbers up in a different way helps them understand the value of the numbers — that the 2 in 26 and the 3 in 32 aren’t really 2 and 3 at all, but 20 and 30.
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Mental Math
Teachers also encourage children to think in terms of the connections between numbers. That’s why you’ll probably see a lot about fact families in 2nd grade. These are groups of three numbers that work together in various combinations to create addition and subtraction facts — 4, 6, and 10, for example. When kids see these numbers together, they can create an addition sentence of 6 plus 4 equals 10. If asked for the result of 10 minus 6, they can easily find the correct answer of 4.
Recognizing when to use doubles or count by 2’s, 5’s, and 10’s also helps kids do mental math. If you know that 9 plus 9 equals 18, then 9 plus 8 must be 17. If you know your multiples of 5, and are asked to find the sum of 9 plus 5, you can quickly find the sum of 10 plus 5, or 15, and take one away, to get the correct answer of 14.
In addition to working on computation skills, 2nd grade teachers do many hands-on activities to reinforce number sense. Each morning at calendar time, my daughters’ teacher used coins to count up the days they’d been in school. If it was the 96th day of school, the class discussed the various ways they could make 96 with coins. “The calendar can be used for so many purposes in math,” says Melissa Symczak, 2nd grade teacher at Brookdale Avenue School in Verona, New Jersey. “I ask the children if the date is even or odd or, if today is the fourteenth, what would be the date two weeks later?”
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Adding On
Once kids feel confident with their number sense and computation skills, teachers can move onto the concept of “regrouping.” This is a general term used to describe moving groups of ten from one column to the other when adding or subtracting. It’s also known as “carrying” in addition and “borrowing” in subtraction, terms that are probably the ones you were taught. Teachers typically start with carrying over, the easier of the two concepts. One trick teachers use is to have students draw a box around a carried-over digit, to help them keep the supplemental number from changing the meaning of the original number. With lots of practice, carrying and borrowing become second nature.
Your child’s teacher will continue to build on her ability to tell time. This year, she’ll be expected to tell time to the quarter-hour. In addition, the concept of elapsed time will be added so that your child can identify the length of time between, say, 11:00 and 4:00.
Despite all the worksheets, computation and new challenges of 2nd grade math, teachers still strive to help their students go beyond the basics. Helping kids see the meaning behind the math will help them grasp tricky concepts, boost their computation skills and confidence, and prepare them for the challenges of multiplication and division to come in 3rd grade.
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