It's important that second-graders memorize basic addition and subtraction facts as soon as possible. Otherwise, as the rest of the class moves on to adding and subtracting with two- and three-digit numbers, your child will be left behind. Any student who has to count on his fingers to solve two-digit addition problems will probably not be able to complete his work in a timely manner. In addition, students who do not have these facts memorized tend to make simple mistakes in calculation. Keep a set of addition and subtraction flash cards at home, and practice them after dinner or while in the car. Have a race to see who can provide the answer the fastest. There are also many free math games on the Internet for practicing basic addition and subtraction facts.
A large chunk of second-grade math curriculum is devoted to teaching the students how to tell time. Reinforce these concepts at home by asking your child to calculate how much time is left before you have to go somewhere, or until your favorite television show is on. In addition, if you don't have an analog (nondigital) clock, consider getting one. Many children struggle with telling time simply because they've never seen a round, analog clock with numbers.
Money, along with time, is an important part of the second-grade math curriculum. Our country is one of the few developed countries that does not put numerals on our coins. This makes it hard for children to learn the value of coins, as they have to look at the size, color and picture. Imagine going to another country and having to figure out the amount of a coin based on the profile of a past president of that country, and you get a glimpse of why monetary concepts can be so hard for children to grasp. Then throw in the fact that one of the smallest coins (the dime) actually has a greater value than larger coins (nickels and pennies), and you get some confused children. Help your child sort it all out by letting him handle and use money at home as much as possible. Familiarity and memorization is the best way for young children to get a grasp on these concepts. In addition, practice counting by twos, fives and tens, because these skills are important for counting money.
Second grade is usually when students start to be exposed to word problems. These are usually difficult for students to solve. Help your student at home by asking her to solve one word problem every day, even if it isn't on her homework. Make it fun by creating problems that have meaning and are even silly, such as those that feature members of the family. Practice them orally, or create a book of written word problems, complete with illustrations.