Toán Lớp 6: Bài 1: Tính
a. (- 12) + (- 23) + 42
b. 99 + (- 5) + (- 104) + 11
c. (- 4) + 78 + (- 16) + (- 21)
d. 22 + (- 7) + (- 19) + (- 14)
giúp mik ạ
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Toán Lớp 6: Bài 1: Tính
a. (- 12) + (- 23) + 42
b. 99 + (- 5) + (- 104) + 11
c. (- 4) + 78 + (- 16) + (- 21)
d. 22 + (- 7) + (- 19) + (- 14)
giúp mik ạ
Comments ( 2 )
Lời giải và giải thích chi tiết:
a. (- 12) + (- 23) + 42
= – 35 + 42
= 7
b. 99 + (- 5) + (- 104) + 11
= 99 – 109 + 11
= -10 + 11
= 1
c. (- 4) + 78 + (- 16) + (- 21)
= ((-4) + (-16)) + ( 78 – 21 )
= -20 + 57
= 37
d. 22 + (- 7) + (- 19) + (- 14)
= (-7) + (-14) + 22 + ( -19 )
= -21 + 22 – 19
= 1 – 19
= -18
chúc bạn học tốt !!!
cho mik ctlhn nhá tks :333
$a)$ $\left(-12\right)+\left(-23\right)+42$
$=\left[\left(-12\right]+\left(-23\right)\right)+42$
$=-35+42$
$=7$
_______________________________
$b)$ $99\:+\:\left(-\:5\right)\:+\:\left(-\:104\right)\:+\:11$
$=\left[99+11\right]+\left[\left(-5\right)+\left(-104\right)\right]$
$=110-109$
$=1$
_______________________________
$c)$ $\left(-\:4\right)\:+\:78\:+\:\left(-\:16\right)\:+\:\left(-\:21\right)$
$=\left[\:\left(-\:4\right)\:+\:\:\left(-\:16\right)\:+\:\left(-\:21\right)\right]\:+\:78$
$=-41+78$
$=37$
_______________________________
$d)$ $22\:+\:\left(-\:7\right)\:+\:\left(-\:19\right)\:+\:\left(-\:14\right)$
$=\:22\:+\:\left[\left(-\:7\right)\:+\:\left(-\:19\right)\:+\:\left(-\:14\right)\right]$
$=22+\left(-40\right)$ $=22-40$
$=-18$