如题所述
先把3.4拆分成 3+0.4，然后用分配律计算。
3.4×5+2.8
=（3+0.4）×5+2.8
=3×5+0.4×5+2.8
=15+2+2.8
=19.8
3.4×5+2.8
=（3+0.4）×5+2.8
=3×5+0.4×5+2.8
=15+2+2.8
=19.8
温馨提示：答案为网友推荐，仅供参考
第1个回答 2021-04-18
解析：依题意可得，
3.4×5+2.8
=（3+0.4）×5+2.8
=3×5+0.4×5+2.8
=15+2+2.8
=19.8
3.4×5+2.8
=（3+0.4）×5+2.8
=3×5+0.4×5+2.8
=15+2+2.8
=19.8
第2个回答 2021-04-18
3.4ⅹ5+2.8=19.8
=(3+0.4)x5十2.8
=(3Ⅹ5)+(0.4x5)+2.8
=15十2十2.8
=19.8
=(3+0.4)x5十2.8
=(3Ⅹ5)+(0.4x5)+2.8
=15十2十2.8
=19.8
第3个回答 2021-04-18
3.4*5+2.8=3.4*10/2+2.8=34/2+2.8=17+2.8=19.8
