In the second grade of primary school, I perfected the multiplication table, learned division and mixing operations, and learned basic geometric figures.
In the third grade of primary school, I learned multiplication and exchange law, geometric area and perimeter, time and unit. Distance calculation, distribution law, fractional decimal.
In the fourth grade of primary school, the natural number of line angle is an integer, the prime factor is trapezoidal symmetry, and the fractional decimal is calculated.
Fractional decimal multiplication and division in the fifth grade of primary school, algebraic equation and average value, comparative size transformation, graphic area and volume.
Proportional percentage probability of sixth grade in primary school, circular fan-shaped cylinder and cone.
Grade?One
Area of triangle = base × height ÷2. The formula S= a×h÷2.
Square area = side length × side length formula S= a×a
Area of rectangle = length× width Formula S= a×b
Additive commutative law: Two numbers are added to exchange addends and keep the same position.
2. Law of additive combination: When three numbers are added, the first two numbers are added first, or the last two numbers are added first, and then the third number is added, and the sum remains unchanged.
3. Multiplication and exchange law: when two numbers are multiplied, the position of the exchange factor remains unchanged.
4. Multiplication and association law: three numbers are multiplied, that is, the first two numbers are multiplied first, or the last two numbers are multiplied first, and then the third number is multiplied.
Second grade:
Appendix+Appendix = Sum
And-one addend = another addend
Negative-negative = difference
Negative difference = negative
Difference+Minus = Minus
Factor × factor = product
Product ÷ One factor = another factor
Dividend = quotient
Dividend = divisor
Quotient × Divider = Divider