When multiplying decimals, we need to count the number of decimal places in each factor and add them up. This sum tells us the number of decimal places in the product. For example, if we multiply 0.3 by 0.4, we have one decimal place in each factor, so we have two decimal places in the product:
0.3×0.4=0.12
In this question, we have 0.75 and 0.8 as the factors. Each of them has one decimal place, so we add them up and get two decimal places for the product. However, when we multiply 0.75 by 0.8, we get 0.6 as the product. This is because the product is smaller than both factors, since they are both less than one. The product has only one non-zero digit after the decimal point, so we do not need to write any extra zeros to fill up the two decimal places. We can simply write 0.6 as the answer.
Therefore, 0.75 * 0.8 has only one decimal place in the product because the product is smaller than both factors and has only one non-zero digit after the decimal point.
I hope this explanation was clear and helpful.