How Many Nines?

 

How many nines will there be in the product of the above multiplication operation?

What is a shorter way of answering this problem?

Number Strips

via @mathequalslove
 

Easy exploration

 

Problem 125: Million Dollar Question

Rich Tasks 57: Four Twos

Problem 116: The Mistery Multiplication

Find all the unknown numbers shown with dots.

source

Rich Tasks 19: Number Challenge

Problem 35: 2-Digit Numbers Challenge

Choose any of the four integers 10 to 99.

Using each of the addition, subtraction, multiplication and division operations one time at most, what is the

                i.         highest number can you get?

               ii.         lowest number can you get?