a)
\(37.24 + 37.76 + 63.79 + 21.63\)
\(=37.(24+76)+63.(79+21)\)
\(=37.100+63.100\)
\(=3700+6300\)
\(=10000\)
b)
\(101 + (-60)+29 + (-40)\)
\(=101-60+29-40\)
\(=(101+29)-(60+40)\)
\(=130-100\)
\(=30\)
c)
\(40+(139-172+99)-(139-199-127)\)
\(=40+139-172+99-139+199+127\)
\(=(139-139)+40+(99+199)-(172+127)\)
\(=0+40+298-299\)
\(=40-1\)
\(=39\)
d)
\((158.129-158.39):180\)
\(=[158.(129-39)]:180\)
\(=(158.90):180\)
\(=158.\)\(\dfrac{1}{2}\)
\(=79\)
a) 37.24 + 37.76 + 63.79 + 21.63
= 37.(14 + 76) + 63.(79 + 21)
= 37.100 + 63.100
= 100.(37 + 63)
= 100.100 = 10000
b) 101 + (-60) + 29 + (-40)
= (101 + 29) + [(-60) + (-40)]
= 130 - 100
= 30
c) 40 + (139 - 172 + 99) - (139 - 199 - 127)
= 40 + 139 - 172 + 99 - 139 + 199 + 127
= 40 + 99 + 199 + 127
= 465
d) (158.129 - 158.39) : 180
= 158.(129 - 39) : 180
= 158 . 90 : 180
= 158 : 2
= 79
