tính nhanh:
\(74\frac{19}{35}\).\(\frac{7}{90}\)+\(15\frac{16}{35}\):\(\frac{90}{7}\)
giúp mình nè : tính nhanh\(a,\frac{1}{7}+\frac{1}{91}+\frac{1}{247}+\frac{1}{775}+\frac{1}{1147}\)
\(b,74\frac{19}{35}.\frac{7}{90}+15\frac{16}{35}.\frac{7}{90}\)
CẢM ƠN CÁC BẠN!!!
a.\(74\frac{19}{35}.\frac{7}{90}+15\frac{16}{35}.\frac{7}{90}+2\frac{14}{90}\)
b,\(\left(\frac{-2}{5}+\frac{3}{7}\right)-\left(\frac{4}{9}+\frac{12}{20}-\frac{13}{35}\right)+\frac{7}{35}\)
AI GIAI DUOC MINH CHO 20 TICK
a) \(74\frac{19}{35}.\frac{7}{90}+15\frac{16}{35}.\frac{7}{90}+2\frac{14}{90}\)
= \(\left(74\frac{19}{35}+15\frac{16}{35}\right).\frac{7}{90}+2\frac{14}{90}\)
= 90 . 7/90 + 194/90
= 630/90 + 194/90
= 824/90 = 412/45
b) (-2/5 + 3/7) - (4/9 + 12/20 - 13/35) + 7/35
= -2/5 + 3/7 - 4/9 - 3/5 + 13/35 + 7/35
= (-2/5 - 3/5) + 3/7 - 4/9 + (13/35 + 7/35)
= -1 + 3/7 - 4/9 + 4/7
= -1 + (3/7 + 4/7) - 4/9
= -1 + 1 - 4/9 = -4/9
1) \(79\frac{19}{35}.\frac{7}{90}+15\frac{16}{35}.\frac{7}{90}\)
2)\(\left(3\frac{1}{5}-\frac{1}{11}\right).11\)
3)\(4\frac{1}{5}:\left(2\frac{1}{3}.1\frac{2}{5}\right)\)
4)\(13,2.\frac{15}{64}-\left(\frac{4}{5}+\frac{2}{3}\right):3\frac{2}{3}\)
Tính:
B=(74+19/35).7/90+(15+16/35).7/90
Tính nhanh:
a)\(\frac{5}{30}+\frac{15}{90}+\frac{25}{150}+\frac{35}{210}+\frac{45}{270}\)
b)\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{56}\)
c)\(\frac{1}{15}+\frac{4}{30}+\frac{2}{45}+\frac{16}{60}+\frac{25}{75}+\frac{36}{90}+\frac{49}{105}+\frac{64}{120}+\frac{81}{135}\)
a) 5/30+15/90+25/150+35/210+45/270
=1/6+1/6+1/6+1/6+1/6
=1/6 x 5
=5/6
b) 1/2+1/6+1/12+1/20+....+1/56
=1/1x2+1/2x3+1/3x4+1/4x5+.....1/7x8
=1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+.......-1/7+1/7-1/8
=1/1-1/8
=7/8
c) mình chịu
chịu,khó quá,nhất là câu c ý
Tính nhanh:
\(A=\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left(\frac{1}{4}+\frac{1}{7}-\frac{-3}{35}\right).\frac{-4}{3}}\)
giải chi tiết
7/9 * 5/14 *3/10 * 8/13
5/13 * 7/8 * 26/15 * 4/14
74 19/35 *7/90 + 15 16/35 * 7/90
( 13 1/2 * 6 3/5 ) * ( 3 1/9 * 2 3/11)
ai làm nhanh mình tick nhé
nhớ làm cả bài nhé
\(\frac{19}{35}+\frac{15}{19}+\frac{16}{35}+\frac{23}{19}+\frac{4}{15}+\frac{11}{15}\)
\(\frac{19}{35}+\frac{15}{19}+\frac{16}{35}+\frac{23}{19}+\frac{4}{15}+\frac{11}{15}\)
\(=\left(\frac{19}{35}+\frac{16}{35}\right)+\left(\frac{15}{19}+\frac{23}{19}\right)+\left(\frac{4}{15}+\frac{11}{15}\right)\)
\(=\frac{35}{35}+\frac{38}{19}+\frac{15}{15}\)
\(=1+2+1\)
\(=4\)
\(\frac{19}{35}+\frac{15}{19}+\frac{16}{35}+\frac{23}{19}+\frac{4}{15}+\frac{11}{15}\)
\(=\left(\frac{19}{35}+\frac{16}{35}\right)+\left(\frac{15}{19}+\frac{23}{19}\right)+\left(\frac{4}{15}+\frac{11}{15}\right)\)
\(=1+2+1\)
\(=4\)
Học tốt
a) \(3\frac{14}{19}+\frac{13}{17}+\frac{35}{43}+6\)
b) \(\frac{\frac{15}{12}+\frac{3}{4}-1}{3-\frac{5}{6}+\frac{2}{3}}+\frac{\frac{16}{5}+\frac{16}{7}-\frac{16}{9}}{\frac{17}{5}+\frac{17}{7}-\frac{17}{9}}\)
\(3\frac{14}{19}+\frac{13}{17}+\frac{35}{43}+6\)
\(=\frac{71}{19}+\frac{13}{17}+\frac{35}{43}+6\)
\(=\frac{1454}{323}+\frac{35}{43}+6\)
\(=5,...+6\)
\(=11,...\)
\(Bai2a\)\(A=\frac{\sqrt{3}-\sqrt{6}}{1-\sqrt{2}}-\frac{2+\sqrt{8}}{1+\sqrt{2}}\)
\(=\frac{\sqrt{3}\left(1-\sqrt{2}\right)}{1-\sqrt{2}}-\frac{2\left(1+\sqrt{2}\right)}{1+\sqrt{2}}\)
\(=\sqrt{3}-2\)
\(VayA=\sqrt{3}-2\)