What is this number rounded off to the nearest tens of millions?

I will solve question 4.

The question asks to simplify the expression $(b^3 \times b^2) \div b^4$.

Step 1: Simplify the multiplication in the numerator using the rule $x^a \times x^b = x^{a+b}$. $b^3 \times b^2 = b^{3+2} = b^5$

Step 2: Substitute the simplified numerator back into the expression. $\frac{b^5}{b^4}$

Step 3: Simplify the division using the rule $\frac{x^a}{x^b} = x^{a-b}$. $b^{5-4} = b^1 = b$

The simplified label is $b$.

The simplified label would appear as $\boxed{b}$.