# 06. The necessity of memorizing beads formula.

For the basic abacus addition and subtraction calculations movements, the abacus design is one upper bead and four lower beads. There are two sets of unique 5’s complementary addition and subtraction formulas, plus two sets of 10’s complementary addition and subtraction formulas that are the same as the school mathematics progression, and there are two sets of 10’s complementary mixed addition and subtraction formulas used in the class formula mix. There are six sets of 34 formulas in total. These formulas are the key to whether you can learn abacus well. If you study separately, most students can understand and operate. However, with the accumulation of units, the six sets of formulas need to be mixed with the questions, which is quite difficult, testing the teacher's teaching skill and students learning effectiveness.

Whether it is necessary to force students to memorize these formulas, some teachers think it is not necessary, and should let students understand how to match the combination of 5’s and 10’s, and then teach them the skills to use. Students can naturally use it freely. If students are forced to recite these formulas, they may think about which formula to use in their calculations. This will wasting time and using different formulas incorrectly will also cause common errors, which is difficult to correct. We agree that students need to memorize formulas to facilitate teaching. In particular, teaching young children especially under the age of six. If students memorize the formula in advance at home, teachers can focus on the use of formulas and correct finger movements in the classroom, and teaching will be more efficient.

The detail steps are as follows:

(1) Teacher can require the students to memorize the first four sets of formulas, including two sets of 5’s complement addition and subtraction formulas and 10’s complement addition and subtraction formulas. The fifth and sixth sets of formulas do not need to be recited. Teacher demonstrate and lecture through classes to avoid students confusion.

(2) Each group of the formulas require the student to memorize at home prior the next class. For example, when learning the simple addition and subtraction in the first two classes of the introduction, the homework will have a 5’s complement addition formula; when learning the 5’s complement unit, the homework will have to recite 5’s complement subtraction formula, and so on.

(3) When asking students to recite the formula in advance, the teacher should first explain the combination of 5’s and the combination of 10’s. If you can use games to explain, it will increase students impression and interest. Before teaching these formula units, the teacher should confirm that every student is ready.

(4) When teaching in the classroom, students are required to use the correct movement of beads, and each formula is read out loud with fingering, which is more effective, and it can also be known whether the students understand what they have learned.

(5) Each unit is assigned two to three lessons. Before entering the next unit, student need to complete a quiz: the unit has 1 digit 4 rows, 30 questions, and is completed within 10 minutes. If the accuracy rate is 80%, then go to the next unit. If more than half of the students do not meet the standards, they may not practice enough or are not familiar with the formulas. If this is the case, one more class time is necessary.

(6) In the first half year of the course, parents are required to assist in homework and check the answers at home as much as possible. Parents participation in teach will arouse greater interest in students and the learning effect will be more effective.