Answer :
The answer will be 
The answer will be 
The answer will be 
The answer will be 
The answer will be 
The answer will be 
The answer will be 
The answer will be 
Explanation :
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
The rule apply for the multiplication and division is :
The least number of significant figures in any number of the problem determines the number of significant figures in the answer.
The rule apply for the addition and subtraction is :
The least precise number present after the decimal point determines the number of significant figures in the answer.
(1) 

In the given expression, 1.24 has 3 significant figures and 1.564 has 4 significant figures. From this we conclude that least precise number present after the decimal point is 2.
Thus, the answer will be 
(2) 

In the given expression, 5.8 has 2 significant figures and 3.156 has 4 significant figures. From this we conclude that least precise number present after the decimal point is 1.
Thus, the answer will be 
(3) 

In the given expression, 1.24 has 3 significant figures and 2.87 has 3 significant figures. From this we conclude that 3 is the least significant figures in this problem. So, the answer should be in 3 significant figures.
Thus, the answer will be 
(4) 

In the given expression, 8.513 has 4 significant figures and 5.45 has 3 significant figures. From this we conclude that 3 is the least significant figures in this problem. So, the answer should be in 3 significant figures.
Thus, the answer will be 
(5) 

In the given expression, 1.24 has 3 significant figures and 33000 has 2 significant figures. From this we conclude that 2 is the least significant figures in this problem. So, the answer should be in 2 significant figures.
Thus, the answer will be 
(6) 

In the given expression, 4 has 1 significant figures and 7.65 has 3 significant figures. From this we conclude that least precise number present after the decimal point is 2.
Thus, the answer will be 
(7) 

In the given expression, 1000 has 1 significant figures and 3.156 has 4 significant figures. From this we conclude that least precise number present after the decimal point is 3.
Thus, the answer will be 
(8) 

In the given expression, 5.42 has 3 significant figures and 3 has 1 significant figures. From this we conclude that least precise number present after the decimal point is 2.
Thus, the answer will be 