Bài 1
212552:x=326 40000-x=3876 (x+1233)-1978=9876
x=212552:326 x=40000-3876 x+1233=9876+1978
x=652 x=36124 x+1233=11854
x=11854-1233
x=10621
Bài 2
12347+23455+76545
=12347+(23455+76545)
=12347+100000
=112347
123×4×25
=123x(4x25)
=123x100
=12300
2×4×25×50
=(2x5)x(4x25)
=10x100
=1000
765×77+21×765+765+765
=765x77+21x765x765x2
=765x(77+21+2)
=765x100
=76500