100.1+100.5+100.4
tinh nhanh do nha!
Tính nhanh
A)A=1.2+2.3+3.4+....+98.3+99.2+100.1
B)B=1.100+2.99+3.98+...+98.3+99.2+100.1
Tính nhanh 1.100+2.99+3.98+...+99.2+100.1
=1.100 + 2.(100-1) + 3.(100 - 2 ) +..... + 99 .(100 - 98) + 100 .(100 - 99 )
=1.100 + 2. 100 - 1.2 + 3.100 - 3.2 +...+ 99 . 100 - 99 . 98 + 100 .100 - 100.99
= 100 (1 + 2 + 3 +... +100) - (1.2 +3 .2 +...+ 99.98 + 100.99
=100.100.101 /2 - 99.100.101 / 3
= 505000 - 333300= 171700
Đ/S : 171700
tính nhanh . giúp mình nhanh nhek
A= 1.100+2.99+3.98+..+98.3+99.2+100.1
Tính nhanh F = 1.100 + 2.99 + 3.98 + ... + 98.3 + 99.2 + 100.1
F \(=1.100+2.\left(100-1\right)+3.\left(100-2\right)+...+100\left(100-99\right)\)
\(=1.100+2.100-1.2+3.100-2.3+...+100.100-99.100\)
\(=100\left(1+2+3+...+100\right)-\left(1.2+2.3+3.4+...+99.100\right)\)
\(=100.\frac{101.100}{2}-\frac{99.100.101}{3}\)\(=\)\(505000-333300=171700\)
=> F = 171700
đúng cái nhe
Tính nhanh F = 1.100 + 2.99 + 3.98 + ... + 98.3 + 99.2 + 100.1
Tính nhanh F = 1 . 100 + 2.99 + 3 . 98 +.... + 98.3 +99.2 + 100.1
Giúp mình bài này nha
0.1+0.6+1.1+....+100.1+100.6
Tính nhanh 1.100+2.99+3.98+...+98.3+99.2+100.1/1.2+2.3+3.4+...+99.100
Tính nhanh:
a,100.2+100.3+100.4+100.5=??
Theo đề ta có:
100 . 2 + 100 . 3 + 100 . 4 + 100 . 5
= 100 . (2 + 3 + 4 + 5)
= 100 . 14
= 1400
100.2+100.3+100.4+100.5
=100.(2+3+4+5)
=100.14
=1400