* Mixed operations arithmetic exercises (second grade, second semester);
Mixed operations of addition and subtraction can generate exercises within 10, within 20, within 50, within 100, within 500, within 1000, and within 10000 according to the options. It can support continuous addition, continuous subtraction, and mixed operations of addition and subtraction of 3 to 5 numbers; according to learning needs and the difficulty of exercises, you can also customize arithmetic exercises containing decimals, tens, hundreds, and thousands.
Key Points
1. Order of Addition and Subtraction Operations:
In mixed addition and subtraction operations, calculate from left to right. If there are parentheses, calculate the expressions within parentheses first, then the expressions outside. For nested parentheses (small, medium, and large), calculate the innermost parentheses first, then the middle ones, followed by the outermost ones, and finally the expressions outside the parentheses.
2. Complementarity of Addition and Subtraction:
In addition and subtraction, calculations can verify each other, which is known as "checking". For example 8 - 2 = 6; thus, 6 + 2 - 8.
3. Order of Operations:
If parentheses are included in a practice problem, the values inside the parentheses should be calculated first. For example:5 + (2 + 6), first calculate 2+6 to get 5+8, resulting in a final answer of 13.
