Tính nhanh:
a) 47.29-13.29-24.29;
b) 26.7-17.9 + 13.26-17.11;
c) 1167:6 + 33:6;
d) 1754:17 - 74:17 + 20:17.
tính nhanh
\(\text{ 23.17 + 47.71 + 83.23 + 47.29}\)
=23(17+83)+47(71+29)
= 23.100+47.100
=100.(23+47)
=100.70=7000
23.17+47.71+83.23+47.92
=23.(17+83)+47.(29+71)
=23.100+47.100
=2300+4700
=7000
Tính nhanh : 53.29+47.29-53.21-47.21
53 x 29 + 47 x 29 - 53 x 21 - 47 x 21
= 29 x ( 53 + 47 ) - 21 x ( 53 + 47 )
= 29 x 100 - 21 x 100
= 100 x ( 29 - 21 )
= 100 x 8
= 800
thực hiện phép tính
17.54+13.71+17.46+13.29
17.54+13.71+17.46+13.29
= 17.(54+46)+13.(71+29)
=17.100+13.100
=100.(17+13)
=100.30
=3000
a) 13.29+121:11 mũ 2 bằng bao nhiu
Cho
A=3/(4.19)+5/(6.19)+13/(6.37)+13/(13.37) +23/13.75
B=5/(7.6)+8/(7.29)+10/(13.29)+14/(13.53)+22/25.53
Tính A/B
Tính nhanh:
a, (4,25.20).5
Tính nhanh:
a) 492 b) 512
c) 99.100
Tính nhanh:
a) (-48) + 10 + (-22) + (-10)
a) \(\left(-48\right)+10+\left(-22\right)+\left(-10\right)\)
\(=\left[\left(-48\right)+\left(-22\right)\right]+\left(-10+10\right)\)
\(=-70+0=-70\)
Tính nhanh:
a) 752-50.75+252
b) 103.97
\(a.75^2-50.75+25^2\\ =75^2-2.25.75+25^2\\ =\left(75-25\right)^2=50^2=2500\)
\(b.103.97\\ =\left(100+3\right)\left(100-3\right)\\ =100^2-3^2\\ =9991\)
\(a,75^2-50.75+25^2\\ =75^2-2.75.25+25^2\\ =\left(75+25\right)^2=100^2=10000\\ b,103.97\\ =\left(100+3\right).\left(100-3\right)\\ =100^2-3^2=10000-9=9991\)
a) \(75^2-2\cdot25\cdot75+25^2\)
= \(\left(75+25\right)^2\)
= \(100^2=10000\)
b) \(103\cdot97\)
= \(\left(100+3\right)\left(100-3\right)\)
= \(100^2-3^2\)
= \(10000-9=9991\)