Maths's problems

0'856 = 0'9

We are going to round off to tenth. When the next decimal is greater than or equal to five, we round up. In our example, the next decimal is 5, so we put 9 in tenth.

a^4 · a^6 = a^(4+6) = a^10

"a" to de power 4 multiplicated by "a" to the power 6 equals "a" raised to the addition of 4 plus 6. The result is "a" to the power 10.

7/5 : 3/8 = 56/15

Here we have to multiply in cross: We multiplied 7 (the numerator of the first fraction) times 8 (the denominator of the second fraction) and the result (56) is the numerator of the new fraction. And for getting the denominator of the result fraction, we have to multiply 5 times 3 (equals 15).