The swimming pool is 50 meters long. To swim 1 km, you have to swim 20 such lengths. Because 1 km (1000 m) contains as many 50 m, this (50 m) has the same length. So 1000÷50=20 (pieces).

Considering that division and multiplication are reciprocal operations, the meaning of multiplication is a simple operation to find the sum of multiple identical addends. This situation can also be interpreted as: the divisor subtracts the divisor until the remainder value is lower than the divisor.

Extended data:

Properties of division operation

1, the dividend is enlarged (reduced) by n times, and the quotient is correspondingly enlarged (reduced) by n times under the condition that the divisor is unchanged.

2. The divisor is expanded (reduced) by n times, while the dividend is unchanged, and the quotient is correspondingly reduced (expanded) by n times.

3. Nature of division: dividing the dividend by two divisors is equal to dividing by the product of these two divisors. Sometimes simple operations can be performed according to the nature of the division.

Baidu encyclopedia-branch