We present new faster algorithms for the problems of I' and (I', I?)-matching on numeric strings. In both cases the running time of the proposed algorithms is shown to be O(I' n log m), where m is the pattern length, n is the text length and I' a given integer. Our approach makes use of Fourier transform methods and the running times are independent of the alphabet size. O(n\sqrt(m log m) algorithms for the I? -matching and total-difference problems are also given. In all the above cases, we improve existing running time bounds in the literature.