The Romans used the abacus for counting purposes. What were the beads running along the wires of an abacus cal
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The Japanese have yearly examinations and competitions in computations on the soroban. Before the invention of counting machines, people used their fingers and toes, made marks in mud or sand, put notches in bones and wood, or used stones to count, calculate, and keep track of quantities. The first abaci were shallow trays filled with a layer of fine sand or dust. Number symbols were marked and erased easily with a finger. Some scientists think that the term abacus comes from the Semitic word for dust, abq.\nA modern abacus is made of wood or plastic. It is rectangular, often about the size of a shoe-box lid. Within the rectangle, there are at least nine vertical rods strung with movable beads. The abacus is based on the decimal system. Each rod represents columns of written numbers. For example, starting from the right and moving left, the first rod represents ones, the second rod represents tens, the third rod represents hundreds, and so forth. A horizontal crossbar is perpendicular to the rods, separating the abacus into two unequal parts. The moveable beads are located either above or below the crossbar. Beads above the crossbar are called heaven beads, and beads below are called earth beads. Each heaven bead has a value of five units and each earth bead has a value of one unit. A Chinese suan pan has two heaven and five earth beads, and the Japanese soroban has one heaven and four earth beads. These two abaci are slightly different from one another, but they are manipulated and used in the same manner. The Russian version of the abacus has many horizontal rods with moveable, undivided beads, nine to a column.
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An abacus helps when explaining to a child ones, tens and hundreds.  Most teachers when teaching how to add and subtract using regrouping (or borrowing) teach the algorithm but the students do not understand WHY.  An abacus is a way of helping students visualize why we have to carry a one when adding or why we need to regroup a tens to the ones place.
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The link shows how to make calculations using an abacus.  Good luck.
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Try this website. Scroll down to "The Circuit" ---\n\nhttp://www.play-hookey.com/ac_theory/ac_rc_series.html
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They used them for counting way back when.
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The probability of extracting one black bead: 3/10 => the probability of doing the same thing twice is 9/100 ( 3/10 *( 3/10) ).\nSimilary the probability of extracting 2 red beads in a row is 25/100 and the probability of extracting 2 green beads is 4/100.\n\n    The total probability is: (9+25+4)/100 = 38%\n\n    The logic: \n       - 2 consecutive extractions are 2 independent events (the number of beads is not modified between the exactions) that must be both true at the same time (in mathematics this is called an AND).\n      - The probabilities are added in the end as the target event is a logical OR of the 3 independent events (i will have 2 beads of the same colour IF i have 2 red beads OR i have 2 black beads OR 2 green). The formula for adding the probabilities is valid only if the events are independent, like in this case. Otherwise you have to calculate the case when 2 events are simultaneously true and substract this from the sum: p(a OR b) = p(a) + p(b) - p(a AND b). Here you cant have 2 red beds and 2 green ones after 2 extractions, 2 red and two black, etc. So p(a AND b) in the above formula is 0.
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i heard there are tiny metals ranging in size between\nmicrodots and pieces of wire 1/3rd of an inch.
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Today, much of the humans on earth use decimal (base 10) numbering because we have 10 fingers and because it is a convenient numbering system for representing numbers.\n\nBut humans haven't always used decimal representation.  The Romans had their "Roman Numeral" system for counting numbers.  The Chinese and Japanese used ideograms (pictures) to represent different numbers.  So did most cultures.  These numbering systems are not Decimal or Base 10.\n\nThe decimal system we use almost universally on earth today was developed by the arab peoples and is refered to as arabic numeral system or arabic numerals.  Decimal (Base 10) was adopted over the other numeral systems because it is so much easier to do computations in than the other numeral systems. For instance, just try to "carry the one" in Roman Numerals.\n\nComputers use Binary (base 2) number system because it is too difficult to represent multiple states or levels in a transistor or memory device.  For this to work, multiple voltage levels would have to be used and as the electricity flows from circuit to circuit, the voltage level could be affected and change, thus making the numbers unreliable. Computers called analog computers make use of varying voltage levels to represent many values of numbers rather than digital computers which use binary.\n\nIt is easy, however, to represent two states (0 and 1) with two extreme voltage values "on" and "off". Even if they degrade and get some noise introduced, making "off" have some small voltage or "on" have lower voltage, the voltages will still be sufficiently different as to be able to recreate the correct value later in the circuit.\n\nRelying on this system of binary representation has allowed humans to mass produce electronic circuits so small and reliable that you and I can communicate about this over long distances and listen.  So, computer scientists and engineers tend not to mess with this good thing of binary unless there is an economic advantage to doing so.\n\nContrary to what poster said, binary numbers existed before the advent of the computer so they were not made only for computers.  See the wikipedia article on Binary Numeral System below.
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http://webhome.idirect.com/~totton/abacus/
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check this site\nhttp://www.taltech.com/TALtech_web/resources/intro_to_bc/bcpwork.htm
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Just remember when someone asks if you "earned your [Mardi Gras] beads"  they want to know if you know anything about ORAL tradition <wink! wink! nudge! Nudge!>
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Egyptians, men and women, wore beaded necklaces, bracelets, and anklets.  Use wooden colored beads and yarn to make colorful jewelry.  \n\n\n\n\n\n\n\n    These links will provide more information about Egypt:  \nhttp://library.thinkquest.org/15924/\nhttp://www.egyptheart.org/\nhttp://neferchichi.com/
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DIVINING ROD [divining rod] or dowser, stick used in searching for underground water or minerals. This form of divination is still in common use in many parts of the world. The instrument is typically a forked twig. The operator holds the forked ends of the twig close to his body, with the stem pointing forward. When he walks over a spot under which water or the desired mineral lies, the stem of the divining rod is supposedly pulled down. Impartial research, however, has indicated that successes in this method result mostly from chance and possibly also from a heightened sensitivity to visual cues of which the diviner is unaware.\n\n\nFor an opposing point of view:\n\nhttp://realmagick.com/articles/93/993.html
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Steel, copper, and brass (for casings)
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See: http://en.wikipedia.org/wiki/BS_1363
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http://www.wetwebmedia.com/abalones.htm
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I think that the easiest way to do this is by enumeration. \n\nIf there are 3 red beads in a row the 3 blue beads have to be in a row. That's pattern 1.\n\nIf no red bead touches any other red bead, then the pattern has to be RBRBRB. That's patern 2.\n\nIf the red beads are split 2 and 1.\nThen the pattern has to be RRBBRB or RRBRBB.\nIf you flip the first pattern over (which you could do with a bracelet) they are the same, so that's only one pattern.\n\nSo 3 patterns total.