Use 3, 10, 9 and 5 to form an equation, and its result is equal to 24

（10-5）×3+9=24

Seven nines make up the formula and the result is 55
emergency

9*9-(9+9+9-9/9)

Use 2, 3, 6, 9 to form as many equations as possible, which is equal to 24

1:(2 + 6) ÷ 3 × 92:((2 + 6) ÷ 3) × 93:(2 + 6) ÷ (3 ÷ 9)4:(2 - 6) × (3 - 9)5:2 × 6 + 3 + 96:(2 × 6) + 3 + 97:(2 × 6 + 3) + 98:((2 × 6) + 3) + 99:2 × 6 +(3 + 9)10:(2 × 6) + (3 + 9)11:2 × (...

1/56+1/72+1/90+1/110 2/3+2/9+2/27+2/81+2/243+2/729
The two questions are separate. dial the wrong number. It should be 2 / 3 + 2 / 9 + 2 / 27 + 2 / 81 + 2 / 243 + 2 / 729

Question 1:
1/56+1/72+1/90+1/110
=(1/7-1/8)+(1/8-1/9)+(1/9-1/10)+(1/10-1/11)
=1/7-1/8+1/8-1/9+1/9-1/10+1/10-1/11
=1/7-1/11
=11/77-7/77
=4/77
2 questions:
2/3+2/9+2/27+2/81+2/243+2/729
=(1-1/3)+(1/3-1/9)+(1/9-1/27)+(1/27-1/81)+(1/81-1/243)+(1/243-1/729)
=1-1/3+1/3-1/9+1/9-1/27+1/27-1/81+1/81-1/243+1/243-1/729
=1-1/729
=728/729

The least common multiple of 56 and 64

2 / 56 64 - - - 2 / 28 32 - - - 2 / 14 16 - - - 7 8 the largest convention is 2 x 2 x 2 = 8 on the left and the least common multiple is

The least common multiple of 63 and 56
And help me calculate the least common multiple of 15 and 39,

63 = 3x3x7,56 = 2x2x7, take the most prime, the least common multiple = 2x2x3x3x7 = 504
15 = 3x5, 39 = 3x13, LCM = 3x5x13 = 195

1 / 2004 + 2 / 2004 + 3 / 2004 +... 2003 / 2004

1 / 2004 + 2 / 2004 + 3 / 2004 +... 2003 / 2004
=（1+2003）/2004+（2+2002）/2004+.+1002/2004
=1x1001+1/2
=1001 and 1 / 2
If you don't understand this question, you can ask,

Simple calculation 2004 * 2004-2003 * 2003

2004*2004-2003*2003
=(2004+2003)(2004-2003)
=4007
Square difference formula

Brief calculation 2006 * 2005 / 2004

2006*2005/2004
=1003*2005/1002
=1002*2005+2005/1002
=2005+ 2005/1002
=2005+2+ 1/1002
=2007 1 / 1002

2006 * 2005: 2004

Simple calculation:
2006×2004/2005
=（2005+1）×2004/2005
=2005×2004/2005+1×2004/2005
=2004+2004/2005
=2004 and 2004 / 2005
("/" is the fraction line,

Use 3, 10, 9 and 5 to form an equation, and its result is equal to 24