Math 2 Lesson: 28 + 5
1.1. Knowledge to remember
How to set and calculate 28 + 5
8 plus 5 equals 13, write 3 remember 1.
2 add 1 equals 3, write 3
So 28 + 5 = 33
1.2. Math forms
Form 1: Performing the calculation
– Set the calculation and then calculate, perform the addition of numbers in order from right to left.
– Set in vertical columns, numbers in the same row are placed straight together.
– Perform the addition of the numbers of each row in order from right to left.
Form 2: Find the calculation that has a value equal to the given value.
– Perform calculations.
– Match with the given topic results.
Form 3: Math Quiz
– Read and analyze the problem: Determine the given data, the amount of increase or decrease and the requirements of the problem.
– Find a solution: When the problem requires finding the value of “both” or “all”, I often use addition.
– Presentation of the solution: Write the solution, calculation and answer to the problem.
– Check the solution of the problem and the result you just found?
1.3. Solving Textbook Exercises
Perform addition of numbers from right to left.
What calculation does each number 51, 43, 47, 25 represent?
Find the value of the calculations and then answer the questions of the problem.
We have : 38 + 5 = 43; 18 + 7 = 25; 28 + 9 = 37
48 + 3 = 51; 78 + 7 = 85; 39 + 8 = 47.
51 is the result of 48 + 3
43 is the result of 38 + 5
47 is the result of 39 + 8
25 is the result of 18 + 7.
There are 18 chickens and 5 ducks. How many chickens and ducks are there?
Chicken: 18 chickens
Ducks : 5 ducks
All: …. children?
To find the solution, add the number of chickens plus the number of ducks.
Both chickens and ducks have the number of children:
18 + 5 = 23 (child)
Answer: 23 children
Draw a line segment of length 5cm.
– Mark a point on the ruler.
– Right hand hold a pencil, left hand hold a ruler, place the ruler so that the 0cm line coincides with the point just marked, keep the ruler straight, mark the point coincident with the 5cm line on the ruler.
– Continue holding the ruler and then use a pencil to connect the two points you just marked along the edge of the ruler, write the names of the two points.
Students use a ruler with centimeter divisions. Draw from line 0 to line 5.
Using a ruler to connect those two points, we get a line segment 5 cm long.