22.72=36*2, 144=36*3, so the greatest common factor is 36.

23. 16=2*8, 40=5*8, 48=2*3*8, so the greatest common factor is 8.

The least common multiple is 2*3*5*8=240.

24.55 1= 19*29, so the sum of the two numbers is 48.

25.90 =1* 90 = 2 * 45 = 3 * 30 = 5 *18 = 6 *15 = 9 *10, so there are six minutes.

26. Let the middle number be X, then the smaller number is X- 1 and the larger number is X+ 1.

So X(X- 1)(X+ 1)=336 and X=7, so the number of three is 6, 7 and 8.