(27.700 - 24.25.20):(45-40+35-30+25-20+15-10+5)
(27.700 - 24.25.20):(45-40+35-30+25-20+15-10+5)
Tinh nhanh
Tính hợp lí
a) (27.45+27.55):(2+4+6+...+14+16+18)
b) (27.700-24.45.20):(45-40+35-30+25-20+15-10+5)
tính hợp lí
a) 341.67+341.16+659.83
b)42.53+47.156-47.114
c) (44.52.60) / (11.13.15)
d) (168.168-168.58)/110
e) (16.17-5)/ (16.16+11)
f) (27.45+27.55)/(2+4+6+...+14+16+18)
g)(27.700-24.45.20)/(45-40+35-30+25-20+15-10+5)
h)1+6+11+16+...+46+51
5-10+15-20+25-30+35-40+45
5 - 10 + 15 - 20 + 25 - 30 + 35 - 40 + 45
= 45 - 40 + 35 - 30 + 25 - 20 + 15 - 10 + 5
= (45 - 40) + (35 - 30) + (25 - 20) + (15 - 10) + 5
= 5 + 5 + 5 + 5 + 5
= 25
5 – 10 + 15 – 20 + 25 -30 + 35 – 40 + 45 – 50 + 55
5 - 10 + 15 - 20 + 25 - 30 + 35 - 40 + 45 - 50 + 55
= -5 + -5 + -5 + -5 + -5 + 55
= -25 + 55
= 30
thực hiện phép tính sau bằng cách hợp lí nhất:
a)(44.52.60):(11.13.15)
b)(168.168-168.58):110
c)(16.17-5):(16.16+11)
d)(27.45+27.55):(2+4+6+...+14+16+18)
e)(27.700-24.45.20):(45-40+35-30+25-20-10+5)
f)1+6+11+16+..=46+51
25 nhân 4 + 75 nhân + 7 nhan 25 / 5 - 10 + 15 - 20 + 25 - 30 + 35 - 40 + 45
25x4+75x+7x25/5-10+15-20+25-30+35-40+45=2720
tính bằng cách hợp lí ; ( 27 x 700 - 45 x 20) : ( 45 - 40 + 35 - 30 + 25 - 20 + 15 - 10 +5)
\(\left(27.700-45.20\right)\div\left(45-40+35-30+25-20+15-10+5\right)\)
\(=\)\(\left(27.100-45.20\right)\div25\)
\(=\)\(\left(27.35.20-45.20\right)\div25\)
\(=\)\(\left[\left(27.35-45\right).20\right]\div25\)
\(=\)\(18000\div25\)
\(=\)\(750\)
tính nhanh 48 x 700 - 24 x 25 x 20 phần 45 - 40 + 35 - 30 + 25 - 20 + 15 - 10 + 5