The product of the predecessor and the successor of the greatest 2-digit number is

1. 9900

2. 9800

3. 9700

4. none of these

The sum of the successor of the greatest 3-digit number and the predecessor of the smallest 3-digit number is

1. 1000

2. 1100

3. 1101

4. 1099

The number of whole numbers between the smallest whole number and the greatest 2-digit number is

1. 100

2. 99

3. 98

4. 88

If a is whole number such that a + a = a, then a is equal to

1. 0

2. 1

3. 2

4. none of these