We frequently encounter distances in miles (English System), but in the Philippines, we use the metric system, and need to convert miles to kilometers,
We will use the conversion 1 mile = 1.6 km. And we have several ways to make the computation easier. Let us consider two ways.
The easiest way to multiply buy 1.6 is by treating 1.6 as 1 + 0.5 + 0.1. Note that 0.5 is half of 1 and 0.1 is one tenth of 1.
- 30 miles = 30 + ½(30) + 1/10 (30) = 30 + 15 + 3 = 48 km
- 72 miles = 72 + 36 + 7.2 = 115.2 km
- 114 miles = 114 + 57 + 11.4 = 182.4 km
- 205 miles = 205 + 102.5 + 20.5 = 328 km
If we note that 1.6 = 16 / 10, we discover another way to multiply by1.6. Simply double the mile measure 4 times (multiply by 16) and move the decimal point of the final product one place to the left ( divide by 10).
- 30 miles = 30 x 2 → 60 x 2 → 120 x 2 → 240 x 2 → 480 → 48 km
- 72 miles = 72 x 2 → 144 x 2→ 288 x 2 → 576 x 2 → 1152 → 115.2 km
- 114 miles = 114 x 2 → 228 x 2→ 456 x 2 → 912 x 2 → 1824 → 182.4 km
- 205 miles = 205 x 2 → 410 x 2→ 820 x 2 → 1640 x 2 → 3280 → 328 km
| 1 mile is 1760 yards or 5280 feet which is equivalent to 1609.344 meters. For practical purposes we can use the conversion 1 mile = 1.6 kilometers. This is almost 99.5% accurate |
C.) A third way is to double the Mile measure and save it as the minuend; double it again and move the decimal point one place to the left to get the subtrahend; then perform the subtraction.
30 miles = 30 x 2 = 60; 60 x 2= 120 → 12.0; 60 – 12 → 48 km
72 miles = 72 x 2 = 144; 144 x 2=288 → 28.8; 144 – 28.8 = 115.2 km
114 miles = 114 x 2 = 228; 228 x 2=456 → 45.6; 228 – 45.6 = 182.4 km
205 miles = 205 x 2 = 410; 410 x 2 = 820 → 82.0; 410 – 82 = 328 km