15. \( 0.8 \times 9=h \)

Did you know that decimal multiplication can often seem tricky at first, but with a little practice, it becomes a breeze? For this calculation, simply multiply \( 8 \times 9 = 72 \) and then remember that since you started with one decimal place in \(0.8\), you'll place that decimal point back, yielding \(h = 7.2\). One common mistake people make when multiplying decimals is neglecting to count decimal places correctly. Always count how many total decimal places are in the factors before you write your answer. It's like a little math dance—just make sure you keep the rhythm!