1 multiple× multiple = multiple multiple1multiple = multiple multiple/multiple = 1 multiple. Speed × time = distance/speed = time/distance/time = speed. Unit price × quantity = total price/total price = total quantity/quantity = unit price. Work efficiency × working hours = total workload ÷ work efficiency = working hours ÷ total workload ÷ working hours = work efficiency.
The Concept of Mathematical Arithmetic in Grade Five
Additive commutative law: Two numbers are added to exchange the position of the addend, and the sum remains the same. Law of addition and association: when three numbers are added, the first two numbers are added first, or the last two numbers are added first, and then the third number is added, and the sum is unchanged.
Multiplication and exchange law: when two numbers are multiplied, the position of the exchange factor and the product remain unchanged. Multiplication and association law: when three numbers are multiplied, the first two numbers are multiplied, or the second two numbers are multiplied first, and then the third number is multiplied, and the product remains unchanged.
Multiplication and distribution law: when two numbers are multiplied by the same number, you can multiply the two addends by this number respectively, and then add the two products, and the result is unchanged. Law of quotient invariance: in division, the dividend and divisor are expanded by the same multiple at the same time, and the quotient remains unchanged. Divide 0 by any number other than 0 to get 0.