Question

correct or ot correct? 15 - 10 4/5?

and -1 7/8 x 2 3/5 = -180?

Answer 1

for the first one, convert the mixed number into improper fraction:
10 4/5 = 54/5
*how to do it: multiply the denominator (which is 5) by the whole number (which is 10) then add the numerator (which is 4), thus 5*10 + 4 = 54,, while the denominator is still 5, thus it's 54/5,,
then 15 = 75/5,, therefore:
(75-54)/5 = 21/5

for the second, it's not -180... to multiply that, convert the mixed numbers into improper fraction:
-1 7/8 = -15/8
2 3/5 = 13/5
then multiply:
-15/8 * 13/5 = -39/8

so there,, :)