i know that memorizing simple one digit multiplication facts isn't a major feat, but since the whole point of the abacus is to get everything down to following patterns of flicks on the beads, id assume that there is a way of multiplying on the abacus that uses the abacus itself to do the math rather than needing to memorize the multiplication. Am i wrong on this? and if not, i assume that the reason it's not used is simply because it's slower than just doing this method?
The main feature of the abacus is as a storage device for decimal (base 10) numbers. In the end you have to do all the calculation by knowing how to move the beads. The first thing to learn on the abacus is how to count. If you know how to count then you can set the number on the abacus by counting. When you understand how each column corresponds to a decimal digit, then it's faster to just set each digit. You could add numbers using counting as well. You set the right side to the addend and the left side to the augend (the other addend). You can count down the addend and count up the augend. Eventually the right side is zero and the left side is your sum. This can be made faster when you realize that the abacus can count down and up by powers of 10 (1, 10, 100, 1000, etc.) very quickly. The standard quick addition people do on the abacus comes down to them memorizing addition tables for digit wise addition and storing the addend in their head. To multiply, you would put the multiplier on the right side and keep the left side as zero. You count down the multiplier and add the multiplicand to the left side. Eventually the right side is zero and your left side is your product. Unlike with addition, digit-wise multiplication does not work. For example the 10s digit of the multiplier can't just be multiplied with the 10s digit of the multiplicand, since it must be multiplied with the 1s digit, the 10s, digit, the 100s digit, and so on. So the standard quick multiplication on the abacus comes down to memorizing multiplication tables for single digit numbers, multiplying every combination of digits, and using standard quick addition adding them up. In this video they set the multiplicand and multiplier on the abacus to prompt the student to do the problem. It is particularly helpful for blind students that would not be able to read paper but could read the abacus.
Thank you for this videos! I love it ❤
i love your teaching way keep it up!!!!!
i know that memorizing simple one digit multiplication facts isn't a major feat, but since the whole point of the abacus is to get everything down to following patterns of flicks on the beads, id assume that there is a way of multiplying on the abacus that uses the abacus itself to do the math rather than needing to memorize the multiplication. Am i wrong on this? and if not, i assume that the reason it's not used is simply because it's slower than just doing this method?
The main feature of the abacus is as a storage device for decimal (base 10) numbers. In the end you have to do all the calculation by knowing how to move the beads.
The first thing to learn on the abacus is how to count. If you know how to count then you can set the number on the abacus by counting. When you understand how each column corresponds to a decimal digit, then it's faster to just set each digit.
You could add numbers using counting as well. You set the right side to the addend and the left side to the augend (the other addend). You can count down the addend and count up the augend. Eventually the right side is zero and the left side is your sum. This can be made faster when you realize that the abacus can count down and up by powers of 10 (1, 10, 100, 1000, etc.) very quickly. The standard quick addition people do on the abacus comes down to them memorizing addition tables for digit wise addition and storing the addend in their head.
To multiply, you would put the multiplier on the right side and keep the left side as zero. You count down the multiplier and add the multiplicand to the left side. Eventually the right side is zero and your left side is your product. Unlike with addition, digit-wise multiplication does not work. For example the 10s digit of the multiplier can't just be multiplied with the 10s digit of the multiplicand, since it must be multiplied with the 1s digit, the 10s, digit, the 100s digit, and so on. So the standard quick multiplication on the abacus comes down to memorizing multiplication tables for single digit numbers, multiplying every combination of digits, and using standard quick addition adding them up.
In this video they set the multiplicand and multiplier on the abacus to prompt the student to do the problem. It is particularly helpful for blind students that would not be able to read paper but could read the abacus.