<span>1) -2×(-25)×4×(-1,8) = - 360 (-25) </span>× 4 = - 100 (-2) × (-1,8) = 3,6 (-100) × 3,6 = - 360 <span> 2) 2,1×(-4)×(-2,5)×7 = 147 </span> (-2,5) × (-4) = 10 2,1 × 7 = 14,7 10 × 14,7 = 147<span> 3) -0,2×8×(-5)×(-1,25) = - 10 (-0,2) </span>× (-5) = 1 (-1,25) × 8 = - 10 (-10) × 1 = - 10<span> 4) -2</span>²<span>/</span>₇<span>×(-</span>⁵<span>/</span>₁₄<span>)×(-</span>⁷<span>/</span>₈<span>)×</span>⁷<span>/</span>₂₅<span> = - 0,025 </span>⁷/₂₅ × (-⁵/₁₄) = - ⁷ˣ⁵/₂₅ₓ₁₄ = - ⁵/₂₅ₓ₂ = - ¹/₅ₓ₂ = - ¹/₁₀ = - 0,1 (-²/₇) × (-⁷/₈) = ²ˣ⁷/₇ₓ₈ = ²/₈ = ¹/₄ = 0,25 0,25 × (-0,1) = - 0,025<span> 5) -0,4×1</span>¹<span>/</span>₄<span>×(-0,8)×3</span>¹<span>/</span>₃<span> = 1</span>¹/₃<span> (-0,4) </span>× (-0,8) = 0,32 = ³²/₁₀₀ 1¹/₄ × 3¹/₃ = ⁵/₄ × ¹⁰/₃ = ⁵ˣ¹⁰/₄ₓ₃ = ⁵⁰/₁₂<span> </span>³²/₁₀₀ × ⁵⁰/₁₂ = ³²ˣ⁵⁰/₁₀₀ₓ₁₂ = ³²/₂ₓ₁₂ = ³²/₂₄ = ⁴/₃ = 1¹/₃<span> 6) -2</span>¹<span>/</span>₃<span>×(-1</span>²₇<span>)×(-9)×1</span>¹⁰<span>/</span>₂₇<span> = - 37 </span> (-9)×1¹⁰/₂₇ = (-⁹/₁)׳⁷/₂₇ = -⁹ˣ³⁷/₁ₓ₂₇ = - ³⁷/₃ -2¹/₃ × (-1²/₇) = -⁷/₃ × (-⁹/₇) = ⁷ˣ⁹/₃ₓ₇ = ⁹/₃ = 3 3 × (-³⁷/₃) = - ³ˣ³⁷/₃ = - 37
Минус на минус будет плюс. 2минуса=+; 3минуса=-; Можно считать минусы и сразу узнать в ответе (+) или (-). 1)-2×(-25)×4×(-1,8)=-360; 1)-25•4=-100; 2)) -100•-2= 200; 3)) 200• -1,8= -360 2) 2,1×(-4)×(-2,5)×7=147; 1)) -4• -2,5= 10; 2)) 2,1•10= 21; 3)21•7= 147; 3) -0,2×8×(-5)×(-1,25)= -10; 1)) 8•-5=-40; 2)) -40• -1,25= 50; 3)) -0,2•50=-10; 4) -2/7×(-5/14)×(-7/8)×7/25= -1/40= -0,025; 1)) -2/7• -7/8= 1/1• 1/4= 1/4=0,25; Сократили 7и 7 на 7; 2 и 8 на 2; 2)) -5/14• 7/25= -1/2• 1/5= -1/10=-0,1; Сократили 14 и 7 на 7; 5 и 25 на 5 3)) 1/4• -1/10= -1/40; или десятичные удобнее 0,25• -0,1=-0,025; 5) -0,4×1 1/4×(-0,8)×3 1/3= 1 1/3. 1)) -0,4• -0,8= 0,32= 32/100; 2)) 32/100• 1 1/4= -32/100• (4•1+1)/4= 32/100• 5/4= 8/20• 1/1= 8/20; Сократили 32 и 4 на 4; 100 и 5 на 5; 3)) 8/20• 3 1/3= -8/20• (3•3+1)/3= -8/20• 10/3= -8/2• 1/3= -8/6= 4/3= 1 1/3. Сократили 20 и 10 на 10;потом 8/6 на 2;
6) -2 1/3×(-1 2/7)×(-9)×1 10/27= 1)) -2 1/3• -1 2/7= (3•2+1)/3• (7•1+2)/7 = 7/3 • 9/7= 1/1• 3/1= 3;
Сократили 7 и 7 на 7; 9 и 3 на 3;
2)) 3• -9= -27;
3)) -27• 1 10/27= -27• (27•1+10)/27= -27/1• 37/27= -1/1• 37/1= -37;
Сократили 27 и 27 на 27.