Su Jiao Class: Time-division Knowledge Points of Mathematics in Grade Two of Primary School
Learning point
1. There are three hands on the clock face. They are (hour hand), (minute hand) and (second hand). The fastest is the second hand, and the slowest is the hour hand.
2. There are (12) numbers, (12) large squares and (60) small squares on the clock face; There are (1) large cells between every two numbers, that is, (5) small cells.
3, clockwise 1 grid is (1) hours; It takes (5) minutes to walk 1 square and (1) minutes to walk 1 square. It takes (5) seconds for the second hand to go 1 and (1) seconds for the second hand to go.
4. When the hour hand goes 1, the minute hand just goes (1), and the minute hand goes 1 is (60) minutes, which is (1 hour).
1 =60 points
1 min =60 seconds
Two standard methods of writing time:
8: 05: 8: 05
8: 55: 8: 55
Note: When the hands in two watches indicate the same time, you can subtract the previous time from the later time to get the elapsed time.
Summarize the knowledge points of each unit in the first volume of grade two mathematics
First unit
Summary of knowledge points:
1, commonly used length units: meters and centimeters.
2. The measurement unit of shorter objects is usually centimeters, and the measurement unit of longer objects is usually meters.
3. Method of measuring the length of an object: align the left end of the object with the "0" scale of the ruler to see what the scale of the right end of the object is on the ruler. The length of this object is several centimeters.
4. Relationship between meter and centimeter: 1 meter = 100 cm 100 cm = 1 meter.
5. Line segment
⑴ Characteristics of the line segment: ① The line segment is straight; ② The line segment has two endpoints; ③ The length of the line segment can be measured.
⑵ Method of drawing line segments: first aim the pen at the' 0' scale of the ruler, point a point on the top, then aim at the centimeter scale of the length to be drawn, point a point on the top, and then connect the two points.
(3) When measuring the length of an object, when the measurement is not started from the "0" scale, the scale number of the starting point should be subtracted from the scale number of the end point.
6. Fill in the appropriate length unit.
Xiaoming is 1 (m) 30 (cm) tall, his exercise book is 13 (cm) wide, and his pencil is 17 (cm).
Blackboard length 2 (m) Thumbnail length 1 (cm) A bed length 2 (m).
Jingshen 3 (meter) School Run 100 (meter) Competition. The teaching building is 25 meters high.
The baby is 80 (cm) tall, the skipping rope is 2 (m) long, and a tree is 3 (m) tall.
A key is 5 cm long, a pencil box is 24 cm long and the platform is 90 cm high.
The door is 2m high, the classroom is12m long, and the chopsticks are 20cm long.
The second grade mathematics unit knowledge point Su Jiaoban.
Summary of knowledge points:
One, two digits plus two digits
1, two-digit plus two-digit non-carry addition calculation rule: align the same numbers vertically, and then add the numbers on the same numbers.
2. The calculation rules of two-digit plus two-digit carry addition: ① the same digits are aligned; (2) from the unit; (3) exactly ten into ten equals 1.
3. When writing, add two numbers, and the same numbers should be aligned. Starting from single digits, add "1" to the tenth digit for every full digit. Don't leave out "1" when adding the tenth digit.
4. Sum = Appendix+One Appendix = and-Another Appendix
Two digits minus two digits.
1, two-digit subtraction without abdication: the same number is vertically aligned, and then the number on the same number is subtracted.
2. Written calculation rules for two-digit subtraction and two-digit abdication subtraction: ① Same digit alignment; (2) from the unit; (3) If the number of digits is not enough, extract 1 from the ten digits, add 10 to the number of digits and subtract it.
3. When writing, subtract two numbers from two numbers, and align the same numbers. Starting with single digits, single digits are not enough. Starting from the tenth digit, subtract 1, add 10 to the single digit and then subtract. When calculating ten digits, the backward 1 should be subtracted before calculation.
4. Difference = minuend-Meimei = Meimei+Differential Meimei = Meimei+Difference.
Third, add and subtract and add and subtract.
1, plus or minus
The writing order of addition and subtraction is the same as that of oral calculation, which is calculated from left to right in turn.
(1) The addition calculation can be done step by step or vertically. The calculation method is the same as adding two numbers. All the same numbers should be aligned, starting with single digits.
② The continuous subtraction operation can be calculated step by step or written as vertical calculation. The calculation method is the same as subtracting two numbers. The same numbers should be aligned, starting with single digits.
2. Add, subtract and mix
The operation order of mixed addition and subtraction formula is the same as vertical writing and addition and subtraction.
3. Add and subtract estimates
In daily life, we don't need accurate calculation, we just need to work out a rough result. In this case, we need to estimate. When estimating, estimate this number to the nearest integer ten and then calculate.
4. When writing vertically, you can calculate the mixed operation of addition and subtraction step by step. The method is the same as adding (subtracting) two numbers. The same number of digits should be aligned and counted from single digits. You can also write in a simple way, in a vertical row. First, complete the calculation of the first step, and then add (subtract) the second number with the result of the first step.
Fourth, solve the problem (application problem)
1, steps: ① Look at the horizontal questions first, write the results, and don't forget to write the unit (the unit is: how much or the words behind) ③ Answer.
2. The application problem of seeking more than the number is added; Find an application problem with a number less than one and calculate it by subtraction (note: subtract a large number).
Jiangsu Education Press related articles on second-grade mathematics knowledge points;
★ Summary of second-grade mathematics knowledge points of Jiangsu Education Edition
★ Review materials of second-grade mathematics knowledge points of Jiangsu Education Edition.
★ Review of knowledge points in the second volume of second grade mathematics of Jiangsu Education Press.
★ Second grade mathematics knowledge points
★ Su classes always review the outline at the end of the second grade mathematics.
★ Review materials of second-grade mathematics of Jiangsu Education Edition
★ Review materials under the second grade mathematics of Jiangsu Education Press.
★ Mathematics review of the second volume of the second grade of Su Jiaoban.
★ Su Jiaoban Grade Two Mathematics Volume II Review Outline
★ Review materials of mathematics in the second volume of Grade 2 of Jiangsu Education Press.