(2 3/4 + 2 1/5) ·16 = (2.75 + 2.2)·16 = 4.95 ·16 = 79.5
(16 ·10⁻ ²)²·13·10⁴ = 16² · 13 ·10^(-4+4) = 16² · 13 = 3328
3.7 ·7.5 : 7.4 = 0.5·7.5 = 3.75
1 8/17 : (12/17 + 2 7/11) = 1 8/17 : (12/17 + 29/11) = 1 8/17 : (132/187 + 493/187) =
= 25/17 : 625/187 = 11/25 = 0.44
(2 1/4 -1 3/19) · 19 = (9/4 - 22/19)·19 = 9/4 · 19 - 22/19 · 19 = 171/4 -22
= 42.75 - 22 = 20.75
(4.9·10⁻³ )(4·10⁻ ²) = 4.9 · 4 · 10⁻⁵ = 19.6 · 10⁻⁵ = 0.000196