bài 2 : Tìm x
( 99,5 - x ) + 3,82 = 30
x + 37,66 = 80,94
76,22 - x = 38,08
36,7- x = 21,205
x + 17,67 = 100 - 63,2
Bài 3 : tính nhanh
15,27 - 4,13 - 1,14
60 - 26,75 - 13,25
38,25 - 18,75 + 21,64 - 11,64 + 9,23
( 72,69 + 18,47 ) - ( 8,47 + 22,69 )
60- 13, 75 - 26,25
15,27 - 4,18 - 2,09
45,28 + 52,17 - 15,28 - 12,17
( 8,27+ 7,16 + 9,33 ) - ( 7,27 + 6,16 + 8,33 )
Bài 2:a)\(\left(99,5-x\right)+3,82=30\)
\(99,5-x=30+3,82=33,82\)
\(x=99,5-33,82=65,68\)
b)\(x+37,66=80,94\)
\(x=80,94-37,66=43,28\)
c)\(76,22-x=38,08\)
\(x=76,22-38,08=38,14\)
d)\(36,7-x=21,205\)
\(x=36,7-21,205=15,495\)
e)\(x+17,67=100-63,2\)
\(x+17,67=36,8\)
\(x=36,8-17,67=19,13\)
Bài 3:
a)\(15,27-4,13-1,14\)
\(=\)\(15,27-1,14-4,13\)
\(=14,13-4,13=10\)
b)\(60-26,75-13,25\)
\(=\)\(60-\left(26,75+13,25\right)\)
\(=60-40=20\)
c)\(38,25-18,75+21,64-11,64+9,23\)
\(=\left(38,25-18,75\right)+\left(21,64-11,64\right)+9,23\)
\(=9,5+10+9,3\)
\(=19,5+9,3=28,8\)
Phần này mk ko chắc đâu nhé.
d)\(\left(72,69+18,47\right)-\left(8,47+22,69\right)\)
\(=72,69+18,47-8,47-22,69\)
\(=\left(72,69-22,69\right)+\left(18,47-8,47\right)\)
\(=50+10=60\)
e)\(60-13,75-26,25\)
\(=60-26,25-13,75\)
\(=33,75-13,75=20\)
g)\(15,27-4,18-2,09\)
\(=15,27-2,09-4,18\)
\(=13,18-4,18=9\)
h)\(45,28+52,17-15,28-12,17\)
\(=\left(45,28-15,28\right)+\left(52,17-12,17\right)\)
\(=30+40=70\)
i)\(\left(8,27+7,16+9,33\right)-\left(7,27+6,16+8,33\right)\)
\(=8,27+7,16+9,33-7,27-6,16-8,33\)
\(=\left(8,27-7,27\right)+\left(7,16-6,16\right)+\left(9,33-8,33\right)\)
\(=1+1+1=3\)
Viết cái đống này mak hoa cả mắt. Mk đã tốn công vậy rùi nên bn nhất định phải k cho mk đó nha.(ko mk giận đó)