1) 19×761 +19×239=14459+4541=19000
2) 87×324-37×324=28188 -10044=18144
3) 4×5/9×3 10/11+5 1/11× 4 5/9=31,9
4/1×5/9=20/9×3 10/11=20/9×43/11=860/99=
=8,7
5 1/11×4 5/9=56/11×41/9=2296 /99=23,2
8,7+23,2=31,9
4) 6,25×17,83-7,83 ×6,25 =111,4375-48,9375=
=62,5
5)7,68×19,91+7,68×80,09=152,9088 +615,0912=
=768
6) 13×13 9/14-5 7/13×12 9/14=107,34
13/1×191/14=2483/14=177,36
5 7/13× 12 9/14=72/13×177/14=12744/182=
=70,02
177,36 -70,02 =107,34