2 = 1 + 1     6 = 2 + 4     8 = 5 + 3     10 = 8 + 2

3 = 1 + 2     6 = 3 + 3     8 = 4 + 4     10 = 7 + 3

4 = 3 + 1     7 = 1 + 6     9 = 8 + 1     10 = 6 + 4

4 = 2 + 2     7 = 5 + 2     9 = 6+ 3     10 = 5 + 5

5 = 4 + 1     7 = 4 + 3     9 = 7 + 2     10 = 10 + 0

5 = 3 + 2     8 = 7 + 1     9 = 5 + 4     10 = 0 + 10

6 = 5 + 1     8 = 6 + 2     10 = 9 + 1     1 = 1 + 0

Tiếng  việt  khó .

NHẢM NHÍ

Lời giải chi tiết:

2=1+1          6=2+4          8=5+3          10=8+2

3=1+2          6=3+3          8=4+4          10=7+3

4=3+1          7=6+1          9=8+1          10=6+4

4=2+2          7=5+2          9=7=2          10=5+5

5=4+1          7=4+3         9=6+3           10=10+0

5=3+2          8=7+1         9=5=4           10=0+10

6=5+1          8=6=2         10=9+1         1=0+1

cop hết mạng kìa

Lời giải chi tiết

10        10       10    10       10      10     10     10    10      5     9     8     7     6   10    1     2     3    4    0

9+1+1+6+0+9+8+7+6+7+6+9+7+54+90+87+890=?

1 + 9 = 10     2 + 8 = 10     3 + 7 = 10     4 + 6 = 10     5 + 5 = 10

10 - 1 = 9     10 - 2 = 8     10 - 3 = 7     10 - 4 = 6     10 - 5 = 5

6 + 4 = 10     7 + 3 = 10     8 + 2 = 10     9 + 1 = 10     10 + 0 = 10

10 - 6 = 4     10 - 7 = 3     10 - 8 = 2     10 - 9 = 1     10 - 0 = 10

=10 , =9,8,7,6,5, =10

1 + 9 = 10     2 + 8 = 10     3 + 7 = 10     4 + 6 = 10     5 + 5 = 10

10 - 1 = 9     10 - 2 = 8     10 - 3 = 7     10 - 4 = 6     10 - 5 = 5

6 + 4 = 10     7 + 3 = 10     8 + 2 = 10     9 + 1 = 10     10 + 0 = 10

10 - 6 = 4     10 - 7 = 3     10 - 8 = 2     10 - 9 = 1     10 - 0 = 10

b)

1 + 9 = 10     2 + 8 = 10     3 + 7 = 10     4 + 6 = 10     5 + 5 = 10

10 - 1 = 9     10 - 2= 8     10 - 3 = 7     10 - 4 = 6     10 - 5 = 5

10 - 9 = 1     10 - 8 = 2     10 - 7 = 3     10 - 6 = 4     10 - 0 = 10

a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)

\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)

\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)

\(=\dfrac{-1621}{126}\)

b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)

\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)

\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)

\(=-\dfrac{49}{20}\)

215

215

Cái này

Đáp án đề thi học sinh giỏi lớp 2 môn Toán

Bài 1: Tính nhanh

a. 10 – 9 + 8 – 7 + 6 – 5 + 4 – 3 + 2 – 1

= (10 – 9) + (8 – 7) + (6 – 5) + (4 – 3) + (2 – 1)

= 1 + 1 + 1 + 1 + 1

= 5

b. 1 + 3 + 5 + 7 + 9 + 10 + 8 + 6 + 4 + 2 + 0

= (0 +10) +(1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5

= 10 + 10 + 10 + 10 + 10 + 5

= 55

a ) 10 - 9 + 8 - 7 + 6 - 5 + 4 - 3 + 2 - 1 

= ( 10 - 9 ) + ( 8 - 7 ) + ( 6 - 5 ) + ( 4 - 3 ) + ( 2 - 1 )

= 1 + 1 + 1 + 1 + 1

= 5

b ) 1 + 3 + 5 + 7 + 9 + 10 + 8 + 6 + 4 + 2 + 0

= ( 10 + 0 ) + ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5 

= 10 + 10 + 10 + 10 + 10 + 5

= 55

a. 10 – 9 + 8 – 7 + 6 – 5 + 4 – 3 + 2 – 1

= (10 – 9) + (8 – 7) + (6 – 5) + (4 – 3) + (2 – 1)

= 1 + 1 + 1 + 1 + 1

= 5

b. 1 + 3 + 5 + 7 + 9 + 10 + 8 + 6 + 4 + 2 + 0

= (0 +10) +(1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5

= 10 + 10 + 10 + 10 + 10 + 5

= 55

a)\(\frac{-3}{5}+\frac{1}{4}+\frac{-3}{10}\)

\(=\frac{-12}{20}+\frac{5}{20}+\frac{-6}{20}\)

\(=\frac{-13}{20}\)

b)\(\frac{1}{5}+\frac{-9}{10}+\frac{-7}{25}=\frac{10}{50}+\frac{-45}{50}+\frac{-14}{50}=\frac{-49}{50}\)

c)\(\frac{1}{5}+\frac{-1}{6}+\frac{1}{7}+\frac{-1}{8}+\frac{1}{9}+\frac{1}{8}+\frac{-1}{7}+\frac{1}{6}+\frac{-1}{5}\)

=\(\left(\frac{1}{5}+\frac{-1}{5}\right)+\left(\frac{-1}{6}+\frac{1}{6}\right)+\left(\frac{1}{7}+\frac{-1}{7}\right)+\left(\frac{1}{8}+\frac{-1}{8}\right)+\frac{1}{9}\)

=\(0+0+0+0+\frac{1}{9}\)

=\(\frac{1}{9}\)