If we multiply and then divide the number by the same thing,
we won't change its value.
Take the number: 58,000,000,000
Divide it by 10¹⁰ : 5.8
Multiply it by 10¹⁰ : 5.8 x 10¹⁰
They want a single digit, so we'll round the 5.8
to the nearest whole number:
6 x 10¹⁰ .