Question

9.99乘7.78加3.33乘6.66（简便计算）

Answer 1

9.99=3×3.33原式=9.99×7.78+3.33×（3×2.22）=9.99×7.78+3.33×3×2.22=9.99×7.78+9.99×2.22=9.99×（7.78+2.22）=9.99×10=99.9望五星采纳~

Answer 2

9.99×7.78+3.33×6.66=3.33×（3×7.78+1×2）=3.33×25.34=77.7222

Answer 3

9.99×7.78+3.33×6.66=9.99×7.78+9.99×2.22=9.99×（7.78+2.22）=99.9