Mathematics
Number patterns
Educator section
Memorandum
7.
a) 1; 3; 6; 10
b).
c) Sketch 5: 15
Sketch 6: 21
10 x (10 +1) ÷ 2
= 55
25 x (25 + 1) ÷ 2
= 325
Leaner section
Content
Activity: number patterns (triangular numbers) [lo 2.3]
7. Let us also investigate TRIANGULAR NUMBERS .
- Look carefully at the following
a) Now complete the following table:
| Sketch | 1 | 2 | 3 | 4 | ||
| Number of triangles |
b) Draw sketches 5 and 6 and complete the table:
C. take note?
We can use the following formula to determine the number of triangles in each sketch:
E.g. Sketch 5 (S 5 ) = 5 × (5 + 1) ÷ 2 = 15
(i) Use the formula and determine (use your pocket calculator if necessary)
_____________________________________________________________________
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- the 10th triangular number __________________________________________
- the 25th triangular number __________________________________________
Assessment
Learning Outcome 2: The learner will be able to recognise, describe and represent patterns and relationships, as well as to solve problems using algebraic language and skills.
Assessment Standard 2.3: We know this when the learner represents and uses relationships between variables in order to determine input and/or output values in a variety of ways using.