Answer: Look at it this way, you are adding 4.2, .5 times. So if you find what 1.5 is of 4.2 you then add that to 4.2. The 1 stands for how many times the number is being multiplied by. So in this case the number is only being multiplied once. Then we move onto the decimal point which says that the number is being multiplied by .5 times. This means that 2.1 (which is half of 4.2) is being added onto 4.2. Hope this makes sense. I always use a calculator for multiplying so its hard to put the process into words haha.
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