<span>а) (79357+2848)+5152=(<span>2848+5152)+79357=8000+79377=87357</span></span>
<span><span>б) (54271+39999)+10001=(39999+10001)+54271=50000+54271=104271</span></span>
<span><span><span>в) 19999+(4801+15200)=(19999+4801)+15200=24800+15200=40000</span></span></span>
<span><span><span><span>г) 18356+(1644+2135)=(18356+1644)+2135=20000+2135=22135</span></span></span></span>