When a number is written in a scientific notation, how can you tell right away whether or not it is greater than or equal to 1?

You can tell with the exponent , if the exponent is a positive the notation will be greater than or equal to zero. Think of it as a number line as you go left it becomes less than zero, as it goes right it because greater than or equal to zero. If the exponent is positive it will go to the right and if the exponents is negative it will go to the left. Hope this help !

The correct answer is $90