Column Tower — Lesson 73: One-digit column practice

What your child does, card by card

One-digit column practice. Practice day! PlayBuddy opens the lesson: “Practice time. Let's get quicker and better.”

First a reminder (“6 + 7 − 4”): the beads build 6, 8, 3, 13, 3 and 9, ring by ring, while your child watches. One line at a time. The beads keep the answer.

Try it: your child works out the column 5 + 8 - 6, with a green ring on the next bead to move.

Five in a row: a mission of 8 tasks with a count of right answers in a row, with the best kept. Your child must work out the columns 3 + 9 - 2, 8 + 7 - 5 + 6 and 9 - 4 + 7 + 5.

In your head: the abacus is covered and your child works out 4 + 3 + 2, 8 - 5 + 4 and 6 + 6 - 3, picking each answer from 7, 8 and 9.

You're ready! One-digit columns, line by line.

What this lesson trains

13 answers in about five minutes. The tasks take 19 bead moves in all: 6 with a top bead and 13 with bottom beads. Numbers reach 17, so the tens rod and the ones rod work. Then 3 quick looks in your head. 5 of the 10 sums need a big friend (“+8 = +3 −5 +10”, “−6 = −10 +5 −1”, “+9 = −1 +10”, “+7 = −3 +10” and “+7 = +2 −5 +10”); the others use free beads.

The first thing your child does: work out the column 5 + 8 - 6.

The sum sheet

In Column Tower the lower window is a sum sheet instead of the hands: the column written out one line under another, the line being worked in yellow, the lines done ticked, and the total once the last line is in. The beads keep the running total, so the abacus is never cleared in the middle of a column.

What PlayBuddy and PlayType say

PlayBuddy: “Don't clear. The beads keep the answer.”

Stars

With 1 or fewer slips across the 13 answers your child earns three stars; 3 or fewer, two.