write the missing number as the letter x:
[tex]4.2+\frac{7}{20}=\frac{420}{100}+\frac{x}{100}[/tex]To solve x:
1. Siplify fraction 420/100 write it in decimals:
[tex]4.2+\frac{7}{20}=4.2+\frac{x}{100}[/tex]2. As 4.2 is possitive in both sides of the equation you substract 4.2 in both sides of the equation:
[tex]\begin{gathered} \text{4}.2-4.2+\frac{7}{20}=4.2-4.2+\frac{x}{100} \\ \\ \frac{7}{20}=\frac{x}{100} \end{gathered}[/tex]3. Multiply both sides of the equation by 100:
[tex]\begin{gathered} 100\cdot\frac{7}{20}=100\cdot\frac{x}{100} \\ \\ \frac{700}{20}=x \end{gathered}[/tex]4. Simplify:
[tex]x=35[/tex]Then, the number in the blank space is 35