20 . заранее за . №1. г) (2 целых 3/7 + 1 целая 5/ целая 4/7+5/9) д) -(2,77-7 целых 2/,23-4 целых 7/9) е) -(5/6+1,,87-1/3)

Г) (2³/₇ + 1⁵/₉)-(1⁴/₇+⁵/₉) = 2³/₇ + 1⁵/₉ - 1⁴/₇ - ⁵/₉ = 1⁶/₇
1) 2³/₇ - 1⁴/₇ = 1¹⁰/₇ - 1⁴/₇ = ¹⁰⁻⁴/₇ = ⁶/₇
2) 1⁵/₉ - ⁵/₉ = 1
3) 1 + ⁶/₇ = 1⁶/₇

д) -(2,77-7²/₉)-(0,23-4⁷/₉) = -²⁷⁷/₁₀₀ + 7²/₉ - ²³/₁₀₀ + 4⁷/₉ = 7
1) -²⁷⁷/₁₀₀ - ²³/₁₀₀ = - ³⁰⁰/₁₀₀ = - 3
2) 7²/₉ + 4⁷/₉ = 11²⁺⁷/₉ = 11⁹/₉ = 10
3) 10 - 3 = 7

е) -(⁵/₆+1,37)-(-2,87-¹/₃) = -⁵/₆ - ¹³⁷/₁₀₀ + ²⁸⁷/₁₀₀ + ¹/₃ = 1
1) -⁵/₆ + ¹/₃ = -⁵/₆ + ²/₆ = - ³/₆ = - ¹/₂ = - 0,5
2) -¹³⁷/₁₀₀ + ²⁸⁷/₁₀₀ = ⁻¹³⁷⁺²⁸⁷/₁₀₀ = ¹⁵⁰/₁₀₀ = 1,5
3) 1,5 - 0,5 = 1