Tính nhanh: 16 x 9 + 18 x 2 =
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
A
0
HT
1
CM
30 tháng 10 2018
18 x 7 + 18 x 16 – 18 x 14 + 18
= 18 x 7 + 18 x 16 – 18 x 14 + 18 x 1
= 18 x (7 + 16 – 14 + 1)
= 18 x 10
= 180
XO
29 tháng 7 2020
\(B=\frac{10}{18}\times\frac{22}{30}\times\frac{36}{44}\times...\times\frac{200}{209}=\frac{1\times10}{2\times9}\times\frac{2\times11}{3\times10}\times\frac{3\times12}{4\times11}\times...\times\frac{10\times20}{11\times19}\)
\(=\frac{1\times10\times2\times11\times3\times12\times...\times10\times20}{2\times9\times3\times10\times4\times11\times...\times11\times19}=\frac{\left(1\times2\times3\times...\times10\right)\times\left(10\times11\times12\times...\times20\right)}{\left(2\times3\times4\times...\times11\right)\times\left(9\times10\times11\times...\times19\right)}\)
\(=\frac{1\times20}{11\times9}=\frac{20}{99}\)
Sửa đề \(C=\left(1-\frac{1}{4}\right)\times\left(1-\frac{1}{9}\right)\times\left(1-\frac{1}{16}\right)\times...\times\left(1-\frac{1}{100}\right)\)
\(=\frac{3}{4}\times\frac{8}{9}\times\frac{15}{16}\times...\times\frac{99}{100}=\frac{3\times8\times15\times...\times99}{4\times9\times16\times...\times100}=\frac{1\times3\times2\times4\times3\times5\times...\times9\times11}{2\times2\times3\times3\times4\times4\times...\times10\times10}\)
\(=\frac{\left(1\times2\times3\times....\times9\right)\times\left(3\times4\times5\times...\times11\right)}{\left(2\times3\times4\times...\times10\right)\times\left(2\times3\times4\times...\times10\right)}=\frac{1\times11}{10\times2}=\frac{11}{20}\)
MN
4 tháng 2 2018
a) \(\frac{3}{16}+\frac{4}{15}+\frac{5}{16}+\frac{1}{15}\)
\(=\left(\frac{3}{16}+\frac{5}{16}\right)+\left(\frac{4}{15}+\frac{1}{15}\right)\)
\(=\frac{1}{2}+\frac{1}{3}\)
\(=\frac{5}{6}\)
b) \(\frac{6}{7}\times\frac{8}{15}\times\frac{7}{6}\times\frac{15}{16}\)
\(=\left(\frac{6}{7}\times\frac{7}{6}\right)\times\left(\frac{8}{15}\times\frac{15}{16}\right)\)
\(=1\times\frac{1}{2}=\frac{1}{2}\)
c) \(\frac{19}{20}\times\frac{13}{21}+\frac{9}{20}\times\frac{8}{21}\)
\(=\frac{19\times13}{20\times21}+\frac{9\times8}{20\times21}\)
\(=\frac{247}{420}+\frac{72}{420}\)
\(=\frac{319}{420}\)
4 tháng 2 2017
11 x 12 + 12 x 13 + 13 x 14 + 14 x 15 + 15 x 16 + 16 x 17 + 17 x 18 + 18 x 19 + 19 x 20 + 20 x 21
= 12 x ( 11 + 13 ) + 14 x ( 13 + 15 ) + 16 x ( 15 + 17 ) + 18 x ( 17 + 19 ) + 20 x 21
= 12 x 24 + 14 x 28 + 16 x 32 + 18 x 36 + 420
= 288 + 392 + 512 + 648 + 420
= ( 288 + 392 ) + ( 512 + 648 ) + 420
= 680 + 1160 + 420
= 1840 + 420
= 2260
tk nha
=
17 tháng 4 2020
Ta có:
11 x 12 + 12 x 13 + 13 x 14 + 14 x 15 + 15 x 16 + 16 x 17 + 17 x 18 + 18 x 19 + 19 x 20 + 20 x 21
= 12 x ( 11 + 13 ) + 14 x ( 13 + 15 ) + 16 x ( 15 + 17 ) + 18 x ( 17 + 19 ) + 20 x 21
= 12 x 24 + 14 x 28 + 16 x 32 + 18 x 36 + 420
= 288 + 392 + 512 + 648 + 420
= ( 288 + 392 ) + ( 512 + 648 ) + 420
= 680 + 1160 + 420
= 1840 + 420
= 2260
#Mạt Mạt#
16x9+18x2
=4x4x9+18x2
=4x36+36
=4x36+36x1
=36x(4+1)
=36x5=180
\(16\times9+18\times2=8\times2\times9+18\times2\)
\(=18\times\left(8+2\right)=18\times10=180\)