(1)7.8÷1.25÷8
=7.8÷(1.25×8)
=7.8÷10
=0.78
(2)0.67×99+0.67
=0.67×(99+1)
=0.67×100
=67
(3)3.76×2.9-1.9×3.76
=3.76×(2.9-1.9)
=3.76×1
=3.76
(4)2.5×3.2×1.25
=(2.5×4)×(0.8×1.25)
=10×1
=10
(5)0.38+9.62÷3.7×5.2
=0.38+2.6×5.2
=0.38+13.52
=13.9
(6)7.8×3.2+7.8×7.8-7.8
=7.8×(3.2+7.8-1)
=7.8×10
=78