Solve the following alphametic, given that two are primes and one is a composite:
SEVEN - THREE = FOUR
BONUS: Without the restriction of the number of composites and primes in the alphametic, how many different solutions are there?
FOUR+THREE=SEVEN
From this list(alphametic solver):
2503+69311=71814
9503+62311=71814
2904+68411=71315
8904+62411=71315
2906+38611=41517
8906+32611=41517
5207+36711=41918
6207+35711=41918
3408+57811=61219
7408+53811=61219
4708+26811=31519
6708+24811=31519
3104+79422=82526
9104+73422=82526
3106+49622=52728
9106+43622=52728
3407+58722=62129
8407+53722=62129
4902+68233=73135
8902+64233=73135
6405+17533=23938
7405+16533=23938
5806+17633=23439
7806+15633=23439
5102+79244=84346
9102+75244=84346
6805+17544=24349
7805+16544=24349
6902+38255=45157
8902+36255=45157
6403+19355=25758
9403+16355=25758
6704+28455=35159
8704+26455=35159
7495+28566=36061
8495+27566=36061
7102+49266=56368
9102+47266=56368
we erase the raws with more than one even number or even number and mult. of 5:
2503+69311=71814
9503+62311=71814
2904+68411=71315 erased
8904+62411=71315erased
2906+38611=41517
8906+32611=41517
5207+36711=41918
6207+35711=41918
3408+57811=61219
7408+53811=61219
4708+26811=31519
6708+24811=31519
3104+79422=82526erased
9104+73422=82526erased
3106+49622=52728erased
9106+43622=52728erased
3407+58722=62129
8407+53722=62129
4902+68233=73135erased
8902+64233=73135erased
6405+17533=23938erased
7405+16533=23938erased
5806+17633=23439
7806+15633=23439
5102+79244=84346erased
9102+75244=84346erased
6805+17544=24349erased
7805+16544=24349erased
6902+38255=45157erased
8902+36255=45157erased
6403+19355=25758erased
9403+16355=25758erased
6704+28455=35159erased
8704+26455=35159erased
7495+28566=36061erased
8495+27566=36061erased
7102+49266=56368erased
9102+47266=56368erased
we are left with:
2503+69311=71814
9503+62311=71814
2906+38611=41517
8906+32611=41517
5207+36711=41918
6207+35711=41918
3408+57811=61219
7408+53811=61219
4708+26811=31519
6708+24811=31519
3407+58722=62129
8407+53722=62129
5806+17633=23439
7806+15633=23439
Too lazy to check for composite/prime - leave it to oyhers.
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PARTIAL SOLUTION
