Build And Use An Abacus

This is a great little tool to use in teaching your children math. It is fun and it is acurate.

The materials that you will need to build you abacus are:

A picture frame

Sting

Thumb tacks

Beads or Buttons

Procedure:

1.) Cut five pieces of string the same length. They should be long enough to cross the picture frame with an extra 7.5 cm (3 inches) on each side for making you knots.

2.) Place five evenly spaced thumbtacks alone each side of the frame.

3.) Slide seven beads (or buttons) onto each string.

4.) Tie the end of one string to the first thumbtack at either side of the frame. Continue tying the strings until you have all five strings tied across the frame.

5.) On all strings, move five beads to the left side of the frame and two beads to the right side of the frame.

6.) Take an additional piece of string that is twice as long as one of the first five. Place your frame so that the five strings are left to right. Tie the new string around the frame at the top about half way across.

7.) With dividing string tied to the top of the frame, bring it down to the next string and tie a knot. Continue on down to the next string and tie another knot. Work your way down to the bottom of the frame until knots have been tied with all the strings. Then tie the string around the bottom of the frame. Now you have the dividing line of your abacus.

Your abacus should now have five strings extending from left to right with five beads on the left side of the dividing string and two beads to the right.



When you are holding the abacus in front of you, the bottom string will represent units. The five beads on the left have a value of one each. The beads on the right will have a value of five each.

The second string represents values of tens. Beads on the left of the divider string represents then units each. Those on the right stand for fifty units each.

The third string stands for hundreds, the fourth string represents thousands, and the fifth string represents ten thousands.

Now we are ready to try a problem. Count out four on your new abacus. To do this, push four beads from the left side of the bottom string to the center. Now add five. To do this you will push one bead from the right side to the center. Now complete the addition problem. (4+ 5 = 9)

Next, go on to subtract six. You will do this by moving the five unit bead on the right back to the frame edge. Then move one of your unit beads on the right back to the frame edge. Wow! We have just solve the subtraction problem. (9 - 6 = 3)

Now lets add eight. Move the five unit bead on the right to the center. Then, move three one unit beads from the left to the center. You will find that you only have two to move. You now have a value of ten. Move the five unit bead on the right back to the frame and the units beads on the right back to the frame. Replace those beads with a value of ten by moving one of the ten unit beads on the second string from the left to the center. Now, move the one unit bead to the center to give you the total of eleven. (3 + 8 = 11)

Now we are ready to try some bigger numbers. Let's try adding 295. Just as you would do in regular addition, add 5 first by moving a 5 bead from the right to the center.

Next add 90 by moving a 50 unit bead from the second string right, and four 10 unit beads from the left.

Finally we add the 200 by moving two of the 100 unit beads on the third string. Your total is now 306. (11 + 295 = 306)

This is such a fun and easy way to teach your child math. Keep trying additional problems and soon you will be using you new abacus quickly and accurately.

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