к : 5 = 1 400 - 900
к : 5 = 500
к = 500 * 5
к = 2 500
проверка :
2 500 : 5 = 1 400 - 900
500= 500
d - 30 = 1 000 - 200
d - 30 =800
d = 800 +30
d =830
проверка :
830 - 30 = 1 000 - 200
800 = 800
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