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根据运算定律和运算性质能推导出很多运算公式,运用这些运算公式可以进行速算。现介绍几种应用公式进行速算的方法,望能对提高同学们的运算能力有帮助。(1)两个首同末合十的两位数相乘。两个两位数,若它们十位上的数都是a,个位上的数分别是b和c,且b+c=10,那么就叫做“首同末合
According to the law of operation and the nature of the operation, many calculation formulas can be deduced, and these calculation formulas can be used for quick calculation. Several methods for applying the formula to speed calculation are introduced here. It is hoped that it will help improve the students’ computing ability. (1) Multiplies the two first and last two digits of the first and last ten. Two two-digit numbers, if the numbers in the ten digits are both a and the numbers in the digits are b and c respectively, and b+c=10, then it is called “first and last”