Using a Hundred Chart to Add Quickly

This is not just for paper. Calendars work like small hundred charts. Moving down one row moves a whole week ahead. This is worth learning because the hundred chart makes number patterns visible all at once. Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Ask yourself where else the same idea might be hiding, then go and look.

You are going to like this one. A hundred chart holds the numbers one through one hundred in rows of ten. To add five, put your finger on the starting number and move five squares to the right, wrapping to the next row if you run off the edge.

To add ten, drop straight down one row, because each row is exactly ten. The chart turns addition into movement your finger can follow and your eyes can check.

Try both moves on the chart. From 45, move right five squares to 50, then down one row to 60. Right for ones, down for tens. Once your fingers know those two moves, the chart does most of the thinking for you. Little by little, this becomes something you just know.