Question

3*4*5+6*8*9+9*12*15+12*16*20分之5*6*7+10*12*14+15*18*21+20*24*

Answer 1

3*4*5+6*8*9+9*12*15+12*16*20 = 3.4.5 + 2(2.3.4) + 3(3.4.5) + 4(3.4.5) = 2(2.3.4) + 8 (3.4.5) = 3.4. (4+40) = 3.4.445*6*7+10*12*14+15*18*21+20*24*28 = 5.6.7 + 2(5.6.7) + 3(5.6.7) + 4(5.6.7) = 10.5.6.7...