My mom was the sort to mentally compute the total for all four of her kids’ back-to-school gear before the cash register did. And I’m pretty good at guestimating tabs, too (I always review receipts and typically find errors). Certainly, math is a part of everyday life, but in this age of graphing calculators and computers that do everything for us, how do we show kids how to connect math to the life they lead? 

“Kids don’t get the connection of math to the real world,” says Glen Whitney, PhD, president of Math Factory, Inc., which will be touring math exhibits nationwide beginning this fall (mathmidway.org) and in 2011 will open the country’s only museum of mathematics in New York. “But when parents give their children the chance to see the connection, math becomes more natural,” notes Dr. Whitney, a former college math professor who now coaches the Mount Elementary School Math Club in Stony Brook, NY and offers engaging ways to help your kids apply math to real life and reinforce the skills they learned in school.

Pack it in. To help your child learn the practical use of geometric shapes, ask him to figure out the best way to fit the most glasses on a shelf. Remind him to notice how the shapes fit together. Then ask him to reorganize a shelf of mugs with handles. How do they fit together to get the most in? Have him explore how turning the handles enables him to fit more. He can learn similar lessons by packing the car trunk for a trip. Or have him organize a box of blocks. 

Hunt for shapes. Look for basic shapes in everyday life and point out how each serves a useful function: equilateral triangles and circles in buildings, semicircles in arches and parabolas on bridges. Why is the shape of the nut on fire hydrants so unusual? Firemen have special tools for accessing hydrants. And why are manhole covers round? So they can’t be put on the wrong way and fall in!

Shop by the numbers. At the grocery store, have your kids estimate how much the total bill will cost, adding and subtracting items as you fill your cart. Make a game of it—the child with the closest guess wins a treat. And have them figure out costs: If two boxes cost four dollars, how much does one box cost? Challenge older kids with per ounce costs. 

Get cooking. Your child can not only practice measuring ingredients and become more familiar with fractions while cooking, he can also reinforce his knowledge of units. How many teaspoons are in a tablespoon, tablespoons in an ounce, ounces in a cup, cups in a pint, pints in a quart and so on? Challenge him by doubling or halving recipes—he’ll need to use division, multiplication and unit conversion skills. 

Develop money sense. Give you child a budget and have her figure out how to stick to it and prioritize her needs and wants. If she gets an allowance, she can calculate how many weeks it will take to save for something special and find the goal date on the calendar. If she spends part of her allowance on other things, she can figure out how much longer her goal will it take. Take a trip to the bank and let her open her own account. She can add deposits in her bankbook, check statements and add interest. 

Create schedules. To reinforce time-management skills, have your child create a realistic schedule of what he can accomplish in a month or a day. How long will each activity take? If it takes 15 minutes to get to a 2:30 p.m. movie, when does he have to leave? If the film lasts one hour and forty-five minutes, when will it end?

Track temperatures. Deciding what to wear? Have your child go outside and guess the temperature. Then have her look at a thermometer (in both fahrenheit and celsius) to see how close she is. 

Measure up. Build something together and have your child measure the items for your project. Planting a garden? Have him measure the distance between each plant and each row. Buying a new gadget? Have him measure whether it will fit in the designated space. 

Play games. Rubik’s Cube, Soma cube, tangrams, Rush Hour, Blokus and Batik all encourage kids to have fun as they explore, discover patterns and fit shapes together. And there are puzzles and-math related games online, too (see below). Even classic word problems, in which you often have to follow a sequence to the end and work backwards, help develop mathematical enthusiasm and keep skills sharp. 

Puzzle over it. Have your child try Sudoko or Kenken (supposedly the world’s most addictive puzzle), which she can find in newspapers or online (sudoku.com, kenken.com). They’ll get her to think creatively as they reinforce her math facts.

Read all about it. There are intriguing books that can help kids get excited about math, learning and exploration. For middle schoolers, try The Number Devil: A Mathematical Adventure, by Hans Magnus Enzensberger, in which a young boy who thinks math is boring dreams about a math devil who takes him on a wild ride of discovery. Also check out The Phantom Tollbooth, by Norton Juster, featuring a kid who takes a fantasy journey where numbers and words come to life.

Travel and learn. On a road trip, ask your child to figure out how many more miles or exits to your final destination. Older kids can use mile markers to calculate how many miles per gallon the car is getting or how long it will take you to reach your destination at the speed you’re traveling. Play a license-plate game, looking for a plate that has the number one, then two, then three and so on; two-digit numbers are tougher. 

Be of service. You child can make a lemonade stand or sell jewelry made from shells she’s collected at the beach, then donate the earnings to charity. She can buy all the ingredients and make price signs, as she hones social skills and an interest in helping her community. She could even take a trip to her charity of choice and deliver her donation. Now that’s putting her number sense to good use.

coolmath4kids.com Addition, subtraction, multiplication, division and fractions for ages 3 to 12.

coolmath.com Prealgebra, algebra and geometry games for ages 13 and up.

coolmath-games.com Thinking and math games and puzzles for all ages.

financeFREAK.com Personal finance lessons for teens.