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.
(a) 628 × 342
![628* 342=214776=2.15* 10^5](https://img.qammunity.org/2020/formulas/chemistry/college/zp3oe6qbrtdr707of595jxqm76pwrp6pid.png)
The correct answer is,
![2.15* 10^5](https://img.qammunity.org/2020/formulas/chemistry/college/3a85gmc69cd174zp4ocw6w6t8w42sa8fdy.png)
(b) (5363 × 102) × (7.4 × 103)
![(5363* 102)*(7.4* 103)=547026* 762.2=(5.47* 10^5)* (7.6* 10^2)=41.572* 10^7=4.2* 10^8](https://img.qammunity.org/2020/formulas/chemistry/college/zhzjfr980ok75q5bh4d46nqzcjpe794i8f.png)
The correct answer is,
![4.2* 10^8](https://img.qammunity.org/2020/formulas/chemistry/college/k201d4wlbg0tz4kexrjxhviyxzk8uo2wku.png)
(c) 28.0 ÷ 13.483
![(28.0)/(13.483)=2.08](https://img.qammunity.org/2020/formulas/chemistry/college/nri7neyrpqozyfi83nhqsb47gwm8irgbxh.png)
The correct answer is, 2.08
(d) 8119 × 0.000023
![8119* 0.000023=0.186737=1.9* 10^(-1)](https://img.qammunity.org/2020/formulas/chemistry/college/e663q4u0mzroye3cp8r1hc1wqrenxkx0p3.png)
The correct answer is,
![1.9* 10^(-1)](https://img.qammunity.org/2020/formulas/chemistry/college/awin6amxvh73f2zd4r32evyz72qd1qxh7h.png)
(e) 14.98 + 27,340 + 84.7593
![14.98+27340+84.7593=27439.7393=2.744* 10^4](https://img.qammunity.org/2020/formulas/chemistry/college/tuysvqxzbjgg2qxle2skfg6at913ig0tsa.png)
The correct answer is,
![2.744* 10^4](https://img.qammunity.org/2020/formulas/chemistry/college/qsz7d5mz3tjbgwqadtoqeh8dc3se878syf.png)
(f) 42.7 + 0.259
![42.7+0.259=42.959=43.0=4.30* 10^1](https://img.qammunity.org/2020/formulas/chemistry/college/v2drg7nyxibcvydkn0pl6ow5y9y6hd3w11.png)
The correct answer is,
![4.30* 10^1](https://img.qammunity.org/2020/formulas/chemistry/college/whdn3bn9bzcfzrmhnfzq464drop0ih3roq.png)