a, 19.64 + 76.34
= 19.64 + 19.4.34
= 19.64 + 19.136
= 19.(64 + 136)
= 19.200
= 3800
b, 35.12 + 65.13
= 35.12 + 65.12 + 65
= 12.(35+65) + 65
= 12.100 + 65
= 1200 + 65
= 1265
a) \(19.64+76.34=95.98\)
b) \(35.12+65.13=100.25\)
c) \(19991999.1998-19981998.1999=10000.9999\)