1/2+...................+71/72
=(1-1/2)+......................+(1-1/72)
=1+1+.....+1-1/2-...................-1/72
=8-(1/2+...................+1/72)
=8-(2-1/1*2+3-2/2*3+.............+9-8/8*9)
=8-(1-1/2+1/2-1/3+1/3-..............+1/8-1/9)
=8-(1-1/9)
=8-8/9
=64/9
Tính nhanh :
a. 5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
b. 1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90+109/110
GIÚP MK VỚI AI NHANH MK TICK
1/2 +5/6+11/12+19/20+29/30+41/42+55/56+71/72
1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
Tính nhanh:
1/2 + 5/6 + 11/12 + 19/20 + 29/30 + 41/42 + 55/56 + 71/72 + 89/90
A=1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90 = ?
A= 1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
A= 1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
1/2 + 5/6 + 11/12 + 19/20 + 29/30 + 41/42 + 55/56 + 71/72 + 89/90
giải hộ mình với
1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90+109/110
