Playing cards and other simple materials can be used at home to practice a variety of skills.

My favorite part of the elementary math textbooks currently in use in our school district, Everyday Mathematics,
is the games.  Games are a great way to engage students in just about
any subject, but are especially helpful in teaching math. Some students
have a lot of anxiety around math that can be sidestepped by making math
seem like play. Math is also a subject that requires a combination of
memorization and problem solving that can be addressed through games.
Students get lots of practice and there are no papers to correct.

The textbook includes a variety of games, some requiring the use of
special equipment that comes with the textbooks, such as a special deck
of cards, and photocopied pages. But I prefer the ones that can be
played with common materials like playing cards. They are easiest to set
up and students can play again at home if they wish. I've even assigned
some of these for homework.

students to practice and then figure out the easiest way to turn it
into a game, with the simplest rules and most readily available
equipment possible. Often I take a known game and modify it. This makes
it easier to get going quickly.

My favorite game from the text is Top It because it is easy to play
and to modify to fit a variety of skills. The game is similar to the
classic card game War. Using many modifications, I've used it to teach
skills such as comparing numbers including decimals and very large
numbers, addition and multiplication, rounding, negative numbers, median
and mean (average).

General rules for all variations:

A deck of cards is used to play the game. Aces counts as 1s, and face
cards are usually removed unless you want to assign some of them values
such as 0.

Each player draws a certain number of cards and turn the cards face
up on the table. (See individual variations below for the number of
cards each player takes and how the value is calculated.)

The player with the hand with the highest value takes all of the cards for the round and puts them in his discard pile.

If two players have cards with the same value, they turn over new
cards and the one with the highest value in this new hand gets all of
the cards for his discard pile.

Play continues until there are no remaining cards (or not enough for a
hand). The player with the most cards in his discard pile is the
winner.

Comparing numbers:

Decide before the game begins how many cards each player will draw.
Each player puts his cards in the order that gives him the highest
number he can get. Each player reads the value of his hand. (Example: We
are playing with 5 cards each. I turn over a 8, 5, 6, 3 and 4. I put
them in this order: 86543, because that will give me the highest number I
can get, and say "Eighty-six thousand, five hundred forty-three." The
other player has 76532, so I take all of the cards and put them in my

Comparing numbers with decimal places:

Decide before the game begins how many cards each player will draw.
Black cards are digits to the left of the decimal point. Red cards are
digits to the right of the decimal point. (Example: We are playing with
four cards each. I turn over a red 3 and 5 and a black 4 and 9. I form
this number 94.53 and read "ninety-four and fifty-three hundredths."}

Rounding:

Decide before the game how many cards each player will draw and what
place you will round to. (Example: We are using four cards and rounding
to the nearest hundred. I get a 3, 7, 2 and 9.  I form 9,732 which
rounds to 9,700.)

Players turn over two cards and add them together. (Example: I turn over a 9 and an 8 and say, "17.")

Multiplication:

Players turn over two cards and multiply them. (Example: I turn over a 9 and an 8 and say, "72.")

Negative numbers:

Red cards are negative numbers and black numbers are positive
numbers. (Example: We are playing with two cards. I turn over a red 9
and a black 6 and say, "Negative 3.")

Median:

Each player turns over three cards and puts them in order from least
to greatest and finds the middle number. This is his score. (Example: I
turn over a 9, 3, and 8. I place them in this order: 3, 8, and 9, and
say, "Eight.") This game also works well with five cards.

Mean (average):

Decide beforehand how many cards each player will draw. Each player
adds up his cards and divides by the number of cards to get the mean.
You may want use calculators for this. (Example: I turn over a 6, 4, and

1. I add these together and get 13 and divide by 3 and get, after
rounding to the nearest tenth, 4.3.)

For all the variations, you can use more or fewer cards depending on
the child's age and skill level and can often increase the number for a
greater challenge as the child has had some practice.

More games online

Everyday Mathematics has posted a few games here: http://everydaymath.uchicago.edu/educators/em_games

I also created a directory of Internet games http://www.elcerritowire.com/learn/ , organized by grade level and subject according to the California state standards