小數速算 (Quick Decimal Math)

當我們將小數乘以或除以 10、100 等 10 的次方數時，可以透過直接移動小數點的位置來快速得出答案。進行乘法時，數值會變大，因此需將小數點向右移動，移動的位數與乘數中「0」的數量相同。相反，進行除法時數值會變小，需將小數點向左移動相應的位數。若在移動小數點時位數不足，則以零作為補位。這是基於十進制位值系統的一種高效運算技巧。

When multiplying or dividing decimals by powers of 10, such as 10 or 100, the answer can be determined quickly by shifting the position of the decimal point. For multiplication, the value increases, so the decimal point is shifted to the right by the same number of places as there are zeros in the multiplier. Conversely, for division, the value decreases, requiring the decimal point to be shifted to the left by the corresponding number of places. If there are not enough digits while moving the decimal point, zeros are added as placeholders. This is a highly efficient calculation technique based on the base-10 place value system.