①a×7.3+7.3×b=7.3×________
②1.25×m×8=________×________×________
①3.12×0.5=________×________
②12.5×8.7×0.8=(________×________)×________
③(2.5+0.6)×4=________×________+________×________
④4.1×1.5+5.9×1.5=(________+________)×________
(2.5+3.7)×□=□×□○□×4
(20+4)×2.5=20×2.5+4×2.5,运用了乘法________律。