I taught 5th grade math last year and many students struggled with multiplying decimals. The important thing to remember is that multiplying decimals with a number in the ones place is really the same concept as multiplying whole numbers. However, multiplying
decimals such as the example 0.47 x 0.18 = t is a bit tricky because what you are actually solving is the question
what fraction is 0.18 of 0.47. The "of" means multiply, but the result is a fraction that is SMALLER than 0.18 and 0.47, so it's more like dividing. The best way to understand these problems is using recipes. For
instance, if I need to find 1/4 of a 1/2 cup, then I multiply 1/4 x 1/2, or in decimal form: 0.25 x 0.5. The answer, of course, will be 1/2 cup divided into 4 parts, which is 1/8 of a cup (0.125).
That is the understanding part. Here is the solving part (which is probably what you did already):
376 (note: don't worry about the decimal point until the END)
Now go back to the original numbers and count the TOTAL number of digits to the RIGHT of the decimal point. 0.47 and 0.18, there are 4 digits, so you need to count 4 place values from right to left like this:
start one two three four
846. ---> 84.6 ---> 8.46 ---> 0.846 ---> 0.0846
Now there are four digits to the right of the decimal point: 0.0846, so t = 0.0846
For the word problem, you will do the same thing. Make sure you line up the numbers so that they look like this:
Don't worry about where the decimals are. If it's easier, just write it without the decimals:
Once you solve this, just remember to place the decimal in the right place!