estimate 6 4/5*1 5/8

Answer 1

7 * 2 = 14

Probably closer to 11.

Answer 2

6 4/5 = 6 + 4 / 5 = 30 / 5 + 4 / 5 = 34 / 5

1 5/8 = 1 + 5 / 8 = 8 / 8 + 5 / 8 = 13 / 8

6 4/5 ∙ 1 5/8 = 34 / 5 ∙ 13 / 8 = 34 ∙ 13 / 5 ∙ 8 =

442 / 40 = 2 ∙ 221 / 2 ∙ 20 = 221 / 20

21 / 20 = ( 220 + 1 ) / 20 = 220 / 20 + 1 / 20 =

20 ∙ 11 / 20 + 1 / 20 = 11 + 1 / 20 = 11 1/20

6 4/5 ∙ 1 5/8 = 221 / 20 = 11 1/20

Answer 3

221 / 20 = ( 220 + 1 ) / 20 = 220 / 20 + 1 / 20 =

20 ∙ 11 / 20 + 1 / 20 = 11 + 1 / 20 = 11 1/20

6 4/5 ∙ 1 5/8 = 221 / 20 = 11 1/20