Bt Tính
—(—315)+(—115)—105+25
888—(—333)—222+70
25×(32+47)—32×(25+47)
Tính các tổng sau:
a) -(-315)+ (-115)- 105+25
b) 888-(-333)-222+111
c) -97-15+44-35-12+98
\(a.\)
\(-\left(-315\right)+\left(-115\right)-105+25\)
\(315-115-105+25\)
\(=215\)
\(b.\)
\(888-\left(-333\right)-222+111\)
\(=888+333-222+111\)
\(=1110\)
\(c.\)
\(-97-15+44-35-12+98\)
\(=-17\)
tính các tổng sau
[ 9 - 18 ) + ( - 17 ) ] + ( - 15 )
666 - ( - 442 ) - 100 - 88
- ( - 315 )+ ( - 115 ) - 105 + 25
888 - ( - 333 ) - 222 + 70
[ ( 9 - 18 ) + ( -17 ) ] + ( -15 )
= [ ( -9 ) + ( -17 ) ] + ( -15 )
= ( -26 ) + ( -15 )
= -41
666 - ( -442 ) - 100 - 88
= 666 + 442 - 100 - 88
= 1108 - 100 - 88
= 1008 - 88
= 920
- ( -315 ) + ( -115 ) - 105 + 25
= 315 + ( -115 ) - 105 + 25
= 200 - 105 + 25
= 95 + 25
= 120
888 - ( -333 ) - 222 + 70
= 888 + 333 - 222 + 70
= 1221 - 222 + 70
= 999 + 70
= 1069
25.(32+47)-32.(25+47)
25.(32+47)-32.(25+47)
= 25.32 + 47.25 - 32.25 +47.32
= 32,(25-25) + 47.(25-32)
= 47.(-7)
= -329
=25.79-32.72
=1975-2304
=-329
25.(32+47) + 32.(25-47)
25.(32+47)+32.(25-47)
= -(25.32+25.47)+(32.25-32.47)
= -25.32+32.47 + 32.25-32.47
= (-25.32+32.25)-(25.47+32.47)
= 0 - 47.(25+32)
= -47.57
= -2649
tinh nhanh 25×(32+47)-32×(25+47)
25 nhân (32-47)-32 nhân(25-47)
Đề:25.(32-47)-32.(25-47)
=25.(-15)-32.(-22)
=-375-(-704)
=329
Dấu . là nhân nha
\(25\cdot\left(32-47\right)-32\cdot\left(25-47\right)=25\cdot32-25\cdot47-32\cdot25+32\cdot47=\left(25\cdot32-32\cdot25\right)+\left(32\cdot47-25\cdot47\right)=0+47\cdot\left(32-25\right)\)
\(=47\cdot7=409\)
tính 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50-999-888-777-666-555-444-333-222-111
nhanh nhé
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31
+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+4
7+48+49+50-999-888-777-666-555-444-333-222-111= -3720
Tinh nhanh:
25.(32+47)-32.(25+47)
25.(32 + 47) - 32.(25 - 47)
= 25.32 + 25.47 - 32.25 - 32.47
= (25.32 - 32.25) + 25.47 - 32.47
= 0 + 47.(25 - 32)
= 47. (-7)
= -329
25.32+25.47-32.25+32.47
(25-25).32+25.47+32.47
0+25.47+32.47
(25+32).47
25.(32+47)-32.(25+47)
=25.79-32.72
=1975-2304
= -329
Bài 3. Bỏ dấu ngoặc rồi tính : a) 245– 32+(-145)+ (-268) b) (-38)–(-147)+(-115) c) (19–47)-(-32)+(68–72) Bài 4. Tính bằng cách hợp lý: a) -45 + 63 – 55– 163 b) 47.(-23)– 23.21 – 23.32 c) -17 + 17.52 – 17.41 d) 25 – (62+25 – 12)