Why do fractions need a common denominator when you add or subtract them?

Weak battery is considered to be a part of routine a. inspection b. wear and tear c. maintenance d. check

How can you find the mean absolute deviation (mad) for this set of data?

How many heads would you expect if you flipped a coin twice? first, fill in the table below with the correct probabilities. hint: the sample space for flipping a coin twice is {hh, ht, th, tt}. a = b = c = f