(1)4.5×3.26+9.7×6.74+3.26×5.2 =3.26×(4.5+5.2)+9.7×6.74 =3.26×9.7+9.7×6.74 =9.7×(3.26+6.74) =9.7×10 =97 |
(2)11.6×4.2+15.8×5.8+4.2×4.2 =4.2×(11.6+4.2)+15.8×5.8 =4.2×15.8+15.8×5.8 =15.8×(4.2+5.8) =15.8×10 =158 |
(3)4.02×3.7-0.02×3.7+3.5×4 =3.7×(4.02-0.02)+3.5×4 =3.7×4+3.5×4 =4×(3.7+3.5) =4×7.2 =28.8 |