The first section of code, ruler, inch, division of understanding

Many handbag factories use steel and soft tape, which are in inches (mainland China does not sell this ruler) we must have a knowledge of the British length system.

Code: English Yard, with the letter "Y".

Ruler: English Crow, using the letter "F" or "'".

Inch: English inch, with the letter "in" or "".

Where the rate conversion relationship:

1 yards = 3 feet

1 feet = 12 inches

1 inches = 8 English cents (especially to keep in mind)

So: 1 British cents Kein 1 8 inches

1/2 British cents S. 16 inches

1/4 British cents S. 32 inches

In the handbag factory, the maximum error value for the handbag's paper lattice is 1/32 inches, (that is, the minimum scale of the steel in inches), and the maximum allowable error for the finished handbag is 1/16 inches.

In Chinese length conversion: 1 m = 3 feet (Hang, Hang), 1 feet = 10 inches, 1 inch = 10 points. Many students are confused with 1-inch = 8-English time-sharing, and a Chinese ruler of 1 inch = 10. For example, China's 3-inch over 1 minutes can be recorded as 3.1 or 31/10 inches, and the length of the foot is 8 inches over 1 British points, students also remember as 3.1 or 31/10 inches this is wrong. Because of the scale in the foot, every 1 inches is divided into 8 lattice, 31/8 or 3.125 inches. 3.1.125; 31. Also such as 4 inches over 5 English points, remember as 45/8 to, remember to 45/10 or 41/2 are wrong, in order to avoid mistakes, we are in the special operation and the calculation, all choose the score. 4 inch over 5 points, remember to make 45/8, remember, use feet, the denominator is 8.

The basic properties of the second section fraction and its operation

Because we use the expression length, when we want to calculate the total length or circumference of the material, in the special operation, we must recognize the basic nature of the score and its operation rules, the detailed knowledge of the students to see the primary school six-year mathematics textbooks tenth book fourth to fifth chapter.

The basic nature of fractions: the numerator and denominator of fractions are multiplied or divided by the same number (except 0), and the value of fractions is unchanged.

such as: 1/2 and 10/24 of the composition of the mother 12 and its size unchanged.

Calculation of fractions

Subtract with the denominator fraction, subtract with numerator, the denominator is invariable.

The different denominator fractions are added minus, first Tong, and then calculated by the method of adding and minus the denominator fraction.

The fraction is multiplied by the fraction, the numerator is multiplied by the molecule, the denominator is multiplied by the numerator, the number is divided by a, which equals the reciprocal of the number.

The application of the third section fraction in the paper lattice

In special work, there is usually such an operation: After a length, take the length of the 1/2, plus the length of a paper. For example: The volume of the front of the bag length of 41/8 inches, width of 4 inches. If: The volume of the front of the bag length is 41/8 inches, width is 4 inches, if the length of the paper mouth is 2/8 inches, length and width of 1/2 plus a paper length is:

Section fourth plane rectangular coordinate system

In the plane there are common origin and two axes perpendicular to each other, which constitutes a plane right angle coordinate system.

Any point in the coordinate plane p, there is a unique pair of ordered real numbers (x, y), and it corresponds; in turn, any pair of ordered real numbers (x, y) can set a unique point within the plane so that its coordinates are (x, y). Therefore, the plane right angle coordinate system, may combine "the number" and "the shape".

Handbags are a three-dimensional, but a single component of handbags, but in the same plane. In order to draw the shape of the handbag component, we can first use the ruler to measure the number of its switch, with these numbers, to determine the point associated with the switch, with a straight line or a smooth curve, connecting these points, you can draw the surface shape of the handbag component. Then we use a compass to zoom in on the edge of the shape of the component's surface, with a length of paper as a unit, and we have the shape of the handbag component. This is the principle and method of the handbag component.

In the future, no matter what shape we encounter, the "coordinate method" can be used to solve it.

### Handbag Craft

- Jun 12, 2017 -