Digit Numbers 1,2,3,4,5,6,7,8,9

Learn to recognise, read and write and write up to 9-digit numbers.

You Know That:

1. Adding 1 to the greatest 1-digit number gives the smallest 2-digit number.
   
   That is, 9+1 is 10.(Ten)
   
2. Adding 1 to the greatest 2-digit number gives the smallest 3-digit number.
   
   That is, 99+1 is 100.(One Hundred)
   
3. Adding 1 to the greatest 3-digit number gives the smallest 4-digit number.
   
   That is, 999+1 is 1000.(One Thousand)
   
4. Adding 1 to the greatest 4-digit number gives the smallest 5-digit number.
   
   That is, 9,999+1 is 10000.(Ten Thousand)
   
5. Adding 1 to the greatest 5-digit number gives the smallest 6-digit number.
   
   That is, 99,999+1 is 100000.(One lakh)
   
6. Adding 1 to the greatest 6-digit number gives the smallest 7-digit number.
   
   That is, 9,99,999+1 is 1000000.(Ten Lakhs)
   
7. Adding 1 to the greatest 7-digit number gives the smallest 8-digit number.
   
   That is, 99,99,999+1 is 10000000.(One Crore)
   
8. Adding 1 to the greatest 8-digit number gives the smallest 9-digit number.
   
   That is, 9,99,99,999+1 is 100000000.(Ten Crores)

The total of 42, 75, 189, 301, and 728 is

The total of 42, 75, 189, 301, and 728 is

A. 1,335.
B. 1,533.
C. 2,301.
D. 1,297.

Right triangle PQR is to be constructed in the xy – plane so that the right angle is at P and line PR is parallel to the-axis. The x and y coordinates of P, Q, and R are to be integers that satisfy the inequalities: –4 ≤ x ≤ 5 and 6 ≤ y ≤ 16. How many different triangles could be constructed with these properties?

Right triangle PQR is to be constructed in the xy – plane so that the right angle is at P and line PR is parallel to the-axis. The x and y coordinates of P, Q, and R are to be integers that satisfy the inequalities: –4 ≤ x ≤ 5 and 6 ≤ y ≤ 16. How many different triangles could be constructed with these properties?

(A) 110 (B) 1,100 (C) 9,900 (D) 10,000

We have the rectangle with dimensions 10*11 (10 horizontal dots and 11 vertical). PQ is parallel to y-axis and PR is parallel to x-axis.

Choose the (x,y) coordinates for vertex P (right angle): 10C1*11C1;

Choose the x coordinate for vertex R (as y coordinate is fixed by A): 9C1, (10-1=9 as 1 horizontal dot is already occupied by A);

Choose the y coordinate for vertex Q (as x coordinate is fixed by A): 10C1, (11-1=10 as 1 vertical dot is already occupied by A). 10C1*11C1*9C1*10C1=9900.


Answer: C.