265+5x2+56x10+56
=265+10+56x10+56
=265+56x(10+10)
=265+56x20
=265+1120
=1385
265+5x2+56x10+56
=265+10+56x10+56
=265+56x(10+10)
=265+56x20
=265+1120
=1385
tinh nhanh
10/56+10/140+10/260+...+10/1400
tinh nhanh ;
127.(27-56)- 27 . (127 - 56)
THUC HIEN PHEP TINH ( TINH NHANH NEU CO THE ) :
1) ( 56 x 46 - 25 x 23 ) : 23
2) ( 28 x 54 + 56 x 36 ) : 21 : 2
3) ( 76 x 34 - 19 x 64 ) : ( 38 x 9 )
4) ( 2 + 4 + 6 + .... + 100 ) x ( 36 x 333 - 108 x 111 )
5) ( 5x 411 - 3 x 165 ) : 410
6) 7256 x 4375 - 725
3650 + 4375 x 7255
tinh nhanh
1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
1 , Tinh nhanh
\(5^{56}.0,008^{19}\)
1) tinh nhanh
a) 85.127+5.127.3
b) 1/2 + 5/6 + 11/2 +19/20 + 29/30 + 41/42 + 55/56 + 71/72 + 89/90
3) tinh gia tri bieu thuc
a) A= 2^2 + 4^2 + 6^2+ ...+ 20^2
b) B= 1^2 + 2^2 + 3^2 +...+ 10^2
tinh nhanh M=3/2-5/6+7/12-9/20+11/30-13/42+15/56-17/72
tinh P=1/1*2+2/2*4+3/4*7+...+10/46*56.
tinh tong M=10\56+10\140 +.............+10\1400