Bài làm :
\(a,35.34+35.38+65.75+65.45\)
\(=35.\left(34+38\right)+65.\left(74+45\right)\)
\(=35.72+65.120\)
\(=2520+780\)
\(=10320\)
\(b,39.8+60.2+21.8\)
\(=\left(39+21\right).8+60.2\)
\(=60.8+60.2\)
\(=60.\left(8+2\right)\)
\(=60.10=600\)
\(c,36.28+36.82+64.69+64.4\)
\(=36.\left(28+82\right)+64.\left(69+4\right)\)
\(=36.110+64.73\)
\(=3960+4672\)
\(=8632\)
\(d,123.1001\)
\(=123123\)
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