A simple method to calculate 0.78 times 98

The simple method of multiplying 0.78 by 98 is 0.78 x 98 = 0.78 x (100-2) = 78-1.56 = 76.44.

1, from a philosophical point of view, multiplication is the result of qualitative change caused by additive quantity. The multiplication of integers (including negative numbers), rational numbers (fractions) and real numbers is a systematic summary of this basic definition.

2. "×" is a multiplication sign, the numbers before and after the multiplication sign are called factors, "=" is an equal sign, and the numbers after the equal sign are called products. 10 (factor) × (symbol) 200 (factor) = (symbol) 2000 (product), also called multiplier.

Extended data:

1, the most commonly used method in simple calculation is the multiplication distribution law. Multiplication and division means ax(b+c)=axb+axc, where A, B and C are arbitrary real numbers. On the contrary, axb+axc=ax(b+c) is called the inverse application of multiplication and division (also called finding common divisor), especially when A and B are complementary to each other, this method is more useful.

2. The distribution law is a simple operation of multiplication, which can be used in fractions and decimals. The main formula is (a+b)c=ac+bc. When the sum of two numbers is multiplied by a number, it can be multiplied by this number first, and then added, and the product is unchanged. This is the so-called law of multiplication and division.

3. The multiplicative associative law is also a simple operation method, which is expressed by letters as (a×b)×c=a×(b×c). Its definition (method) is: multiply three numbers, first by the first two numbers, then by the third number; Or multiply the last two numbers first, and then multiply the first number, and the product remains the same.

References:

Baidu Encyclopedia _ Multiplication Baidu Encyclopedia _ Simple Calculation Baidu Encyclopedia _ Algorithm