Colder and Warmer: The Skating Pond

At the frozen Skating Pond, Coach Nora checks the thermometer before every lesson. In the cold of winter the temperature goes up and down past zero: a little warmer at lunch, much colder at night.

Remember: Colder means the temperature goes down; warmer means it goes up. To go past zero, count down to zero first, then keep going: from 3°C, getting 5 degrees colder is 3 degrees down to 0°C and 2 more, so −2°C. To find how far apart two temperatures are on opposite sides of zero, add their distances from zero: from −4°C to 4°C is 4 + 4 = 8 degrees.

Magic trick: Break it at zero! Go to zero first, then count what is left on the other side.