7263+298 1923-456-544 265×99+265 (250+25)×40 101×87 13×49+49×87 125×25×32 9999+998+97+6.
问题描述:
7263+298 | 1923-456-544 |
265×99+265 | (250+25)×40 |
101×87 | 13×49+49×87 |
125×25×32 | 9999+998+97+6. |
答
(1)7263+298
=(7200+63)+(300-2)
=(7200+300)+(63-2)
=7500+61
=7561;
(2)1923-456-544
=1923-(456+544)
=1923-1000
=923;
(3)265×99+265
=265×(99+1)
=265×100
=26500;
(4)(250+25)×40
=250×40+25×40
=10000+1000
=11000;
(5)101×87
=(100+1)×87
=100×87+87
=8700+87
=8787;
(6)13×49+49×87
=(13+87)×49
=100×49
=4900;
(7)125×25×32
=125×25×4×8
=(125×8)×(25×4)
=1000×100
=100000;
(8)9999+998+97+6
=(10000-1)+(1000-2)+(100-3)+6
=11100-6+6
=11100.