3. Write down all three-digit numbers whose sum of digits is equal to 9. How many are there?
3. These are the numbers: 900,

801, 810,

702, 720, 711,

603, 630, 612, 621,

504, 540, 513, 531, 522,

405, 450, 414, 441, 423, 432,

306, 360, 315, 351, 324, 342, 333,

207, 270, 216, 261, 225, 252, 234, 243,

108, 180, 117, 171, 126, 162, 135, 153, 144.

9 POINTS

There are 45 such numbers.

1 POINT

TOTAL 10 POINTS

Note: Award ONE POINT for every 5 correctly listed numbers.