Найди значение выражение (1 2/7×5 4/9-3 2/3)÷2,5

Question

Математика: Найди значение выражение (1 2/7×5 4/9-3 2/3)÷2,5

balashova1296 · Accepted Answer

5 1/16 - 1   1/8 * (5/6 +3/14) = 3 99/112
выражением:
= 5 1/16 - 9/8 * ( 35/42 + 9/42)=
= 5 1/16   - 9/8 * 44/42 =
= 5 1/16   - 9/8 *   22/21 =
= 5 1/16 - (3*11)/(7*4)=
= 5 1/16 - 1 5/28 =
= 5 7/112 - 1 20/112=
= 3 99/112
по действиям:
1) 5/6 + 3/14 = [( 5*7) / ( 6*7)] + [(3*3)/(14*3)]=35/42 + 9/42 =
=44/42 = 22/21 = 1 1/21
2)1 1/8 * 1 1/21 = 9/8 * 22/21 = (3*11)/(4*7) = 33/28 = 1   5/28
3) 5 1/16 - 1 5/28 = 81/16 - 33/28 = [(81*7)/(16*7)] - [(33*4)/(28*4)] =
= 567/112 - 132/112= 435/112= 3   99/112

MOGZ ответил