SUMIF wildcard , doing manually 300 times will take long

I have this on cell b1

=sumif(sheet1!a:a,"100.*",sheet1!m:m)

If i drag down i have to edit the formula on b2 to wildcard 101 while 101 is on cell a2

Maybe some and formula to tune up this automatically

The series of codes are running numbers as follows on a1 going upto 300

100
101
102

Yes that the AND i was looking for , you saved me from doing it for 300 times , Thanks Norie