Calculator fun

Calculator fun.

Calculators are no substitution for knowing your facts, but sometimes they can be used to make some fun mathematical discoveries.

For grades 1-3

Try multiplying any number by 10.  What do you notice?  Now try multiplying by 100.  Now 1000.  Think you could do it without a calculator now?

Grades 4-5

Same as the younger kids, try multiplying any number by 10 then 100 then 1000.  Seems pretty simple doesn’t it.  You might not need a calculator.  Before you make up a rule though, try multiplying a number like 4.7 by 10, then 100 then 1000.  Now try 2.587. 

Once you feel that you can come up with a rule, try dividing by 10, then 100, then 1000.  Can you figure a rule out for that?

Grades 6-8

Alright, get out you calculator but also paper and pencil.  I’ve got two tricks you might find pretty cool.

Start with a two digit number, like 35 and multiply it by 11.  When you get the answer write it down making the middle number a different color.  Try this several times.  You should start to see a neat pattern forming making it easy to multiply any two digit number by 11 without a calculator.

Now check this out.  Take any two digit number ending in 5, like 45.  Square it (multiply it by itself.)  Write down your answer.  Do this again several times.  What do you notice?  It might take a little while and you may need to ask your parents for some help, but a real nice pattern is there. 

Math Circle Fun

Circle Fun

Grades 1-3

You'll need a ruler for this.  Near the center of a piece of paper make a dot.  Now, measure a distance in any direction from that dot and make another dot.  Do this again measuring the same distance from the original dot now in a different direction.  Keep going back to the same dot and measuring the same distance only in different directions.  When you've done this many times, say at least 10, connect the outer dots.  What if you did this a million times?  What do you think it would form?

Grades 4- 5

Cut a regular piece of paper into strips 3 inches wide.  Roll them up to make 3-inch long tubes less than 2 inches in diameter.  Now, using another piece of paper,  Using either a compass or simply a piece of string, make a circle with radius 1 inch, then 2 inches, then 3 inches and so on.  Cut the circles out to form disks.  Between each disk place a tube and see how high you can build a tower.


Grades 6-8

Using a sewing tape measure, find a something circular in the house.  Measure the distance around the circle.  Now measure the distance across at its widest point (diameter.)  Next take the distance around (this is the circumference) and divide by the diameter.  Record your answer.  Repeat with other circular objects recording your answer each time.  Do you notice something happening?  Anything familiar?

Junk Mail and Mail?

Grades 1-3

Count how many pieces of junk mail make it to the recycling bin each day.  Compare the number of pieces of junk mail to other mail.  Make a big comparison at the end of the week.

Grades 4-5

Junk mail can be pretty heavy.  Keep track of the junk mail that ends up in the recycle bin in your house.  At the end of the week, hold it all while you stand on a bathroom scale.  Then weigh yourself and subtract.  This is how much weight your family recycled in junk mail this week.  Multiply by 52 and you’ll have an idea of how much junk mail comes to your house every year. 

Grades 6-8

Does one day of the week generate more junk mail than the others?  Try setting up a simple line graph for a couple of weeks.  Record the number of pieces that your family receives each day.  Make a prediction for the third week and see what happens.

Rolling the Dice

Rolling the Dice

Using simple tools such as a die or dice is a great way to have children learn their math facts. Here are some simples ways to have children learn addition, multiplication and for more advanced students, try the game of the "24" to challenge knowledge of order of operations.

Materials Needed:
Grades 1-3: 2-3 dice
Grades 4-5: 2-3 dice
Grades 6-8: 4 dice

Grades 1-3
The basic starting point for using dice for learning and reviewing math facts is to have the child roll two dice and add them together. Have the child keep track of each score. Whoever reaches 500 first wins.

If your child has advanced beyond that point, make it more challenging by using three dice. Roll the first die for a target number. Then roll the other two dice until together they add up to the target number of the first die. Add all the various rolls together and the person that has a total of 500 first, wins!

Grade 4-5 

The basic starting point for using dice for children in Grades 4-5, is to roll two dice and have the child multiply them together. If you child is more advanced, have the child roll two dice and add them together and then repeat. Then multiple the two sums. Keep track of each score and the first person to reach 500 first, wins!

Grades 6-8

24 Game
Roll four dice.  Take the four numbers you rolled and use them to make 24.  You can only use the four numbers, but you can use them in any way.  For example:

You roll 6 , 9 , 3 , 2.  
6 + 9 + 3² = 24
You roll 1 , 4 , 9 , 2
2(9 + 4 – 1) = 24

 This activity can be particularly challenging for some number combinations but nearly every one can be done.

These are great ways to keep your math facts sharp throughout the summer.  Have fun with it and keep checking back here for weekly activities that make math fun.