goodsamathritan's answer to Nicole's Primary 6 Maths Fractions Singapore question.
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shaded triangles follow this pattern:
fig 3, 1+2+3
fig 4, 1+2+3+4
fig 32, 1+2+... 31+32.
You can add up the numbers one by one with the calculator but there’s a nice formula for adding up numbers in this sequence. (n x m)/2, where ‘n’ is the number of numbers (in this case, 1 to 32 = 32 numbers and ‘m’ is the ‘magic number’, which is the sum of the first and the last in the sequence; then, divide by 2.
fig 3, 1+2+3
fig 4, 1+2+3+4
fig 32, 1+2+... 31+32.
You can add up the numbers one by one with the calculator but there’s a nice formula for adding up numbers in this sequence. (n x m)/2, where ‘n’ is the number of numbers (in this case, 1 to 32 = 32 numbers and ‘m’ is the ‘magic number’, which is the sum of the first and the last in the sequence; then, divide by 2.
Date Posted:
4 years ago
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