Explications:
[tex] \frac{35 \times 10}{ {10}^{2} } \times 2 \times {10}^{7 } \times {10}^{9} = 70 \times {10}^{19} [/tex]
[tex]124 \times {10}^{11} \times 5 \times {10}^{8} = 620 \times {10}^{19} [/tex]
[tex]31.4 \times {10}^{21} - 4 \times {10}^{20} = {10}^{20} \times 310 [/tex]
[tex]7435 \times {10}^{4} \times {10}^{12} = 7435 \times {10}^{16} [/tex]
