Two petrol prices are written here in little green lights.
What’s the difference in the number of lights making a 6 and the number of lights making an 8?
What’s the difference in the number of lights making a 6 and the number of lights making a 3?
How did you work out your answers?
Answer:
To find the difference, look carefully at the two digits and take the smaller number of lights from the larger number of lights.
This is one way of getting the solution.
Compared to the 6-digit, an 8-digit has
- 1 less light in the middle in the furthest left row of lights,
- 4 more lights in the furthest right row,
- 4 more lights in the next furthest right row, and
- 3 more lights in the next furthest right row.
Altogether the 8-digit has 4 + 4 + 3 – 1 = 10 more lights than the 6-digit.
Compared to a 3-digit, a 6-digit has
- 10 more lights in the 3 rows that are furthest to the left. 10 x 3 = 30.
- 4 less lights in the furthest right row,
- 4 less lights in the next furthest right row and
- 3 less lights in the next furthest right row.
Altogether the 6-digit has 30 – 4 – 4 – 3 = 30 – 11 = 19 more lights than the 3-digit.
