To compare mixed numbers and decimals, convert all to the same form (all decimals or all fractions with a common denominator).

Convert all to decimals:
1 1/2	=	1.50
1 425/1000	=	1.425
1.3	=	1.30
1 1/4	=	1.25
Smallest is 1.25, which is 1 1/4.