The yang fai triangle is the fun part of the second grade math expansion, which looks simple, contains a lot of focused patterns and error-prone spots, and many children seem to understand it and write it wrong. Today's day is dedicated to second-year children, with a central focus, hard to remember, easy to warn, easy to grasp without complicated calculations。
I. What does the yang fai triangle look like (basic focus)
The yang fai triangle is a digital pyramid with an increasing number of layers, from top to bottom, with one more number per layer than the previous layer, which is exactly the same:
First tier: 1
Second floor: 11
Third floor: 1 2 1
Level four: 1 3 3 1
Fifth floor: 1 4 6 4 1
Sixth floor: 1,5 10 10 5 1
Ii. The strategic priority (sure context)
1. Fixed rule 1: 1 on both sides
The number on each floor to the left and the right is always one and never changes。
Whether it's the third, fifth or higher layers, both ends are numbers 1, which is the most basic rule of the yang fai triangle。
2. Fixed rule 2: middle = two digits on shoulder plus (core focus)
This is the most critical and well-tested rule of the yang fai triangle, and it must be remembered:
Each number in the middle of each layer is combined by two numbers on its shoulder。
Examples:
3. Fixed rule 3: around symmetry, like mirrors (memory focus)
Each layer of numbers is exactly the same on the left and on the right, and half of them remember the other half。
For example, on the fifth floor: 1,464,1 with one, four on the left, four, one on the right and six in the middle。
4. Layers and numerical patterns
There's one number on the first level, two on the second level and three on the third level and there's a few numbers on the third level, a pattern that helps the children check to write right。
Iii. Equipment (children's most vulnerable places, focus)
Hard spot 1: unable to find “shoulders”, wrong number
Many children do not know which number is “the number on the shoulder”, and each middle number depends on the two numbers directly above it, not simply added。
Error: add random numbers
Correct: plus only two adjacent numbers above
2. Difficult point 2: faulty number of layers, numbering wrong
It is important that there be only one number for the first layer, from the top to the bottom, and that no second layer be considered the first。
3. Difficult 3: calculating carelessness and miscalculation
The yang fai triangle is all added, and the child is easily miscalculated:
For example, 4+6 = 10, do not count as 9; 3+3 = 6, do not count as 5, do so slowly and carefully。
4. Difficult 4: symmetric pattern wrong
The left and right symmetry is reversed from the center to the side, rather than simply writing numbers that can be checked against them。
Iv. Teaching kids to write with hands
Take the seventh floor, for example:
First one:1: 1 for the sixth floor: 1 + 5 = 6 → 1 + 10 = 15 → 2 + 10 = 20 → 3 + 5 = 15 → 4 + 1 = 6 → 5 & 5 = 6 → 5 & 5 = 6 → 5 & 5 = 6 %
Learning tips (for parents + children)
Remember the rule, then write, and check if the two head are one, number, right or left symmetry from the lower to the sixth floor, and then write the yang fai triangle to learn, observe and learn
Kid, can you write the seventh floor of the yang fai triangle yourself? Which is the hardest rule to remember when you write
Let's see who's the math player
Pay attention to me. Focus on second grade maths. Focus, focus
