Răspuns:
a.3x27=3x(20+7)=
=3x20+3x7=
=60+21=
=81
4x29=4x(20+9)=
4x20+4x9=
=80+36=
=116
2x46=2x(40+6)=
=2x40+2x6=
80+12
b.3x62=3x(60+2)=
=3x60+3x2=
=180+6=
186
=5x71=5x(70+1)=
=5x70+5×1=
=350+5=
=355
4x42=4x(40+2)=
=4x40+4×2=
=160+8=
=168
c.7x36=7×(30+6)=
=7×30+7×6=
=210+42=
=252
5x47=5×(40+7)=
5×40+5×7=
=200+35=
=235
=8x25=8×(20+5)=
=8×20+8×5=
=160+40=
=200
