Estimate the product or quotient subsequence

Note that this subsequence agrees exactly with Khan Academy's.

• Estimate the product, each number can have 2 digits or less (4th grade)
• Estimate the quotient, dividend has up to 4 digits, divisor has 1 digit (4th grade)
• Estimate the product, each number can have any number of digits (5th grade)
• Estimate the quotient, each number can have any number of digits (5th grade)