Times Market — Lesson 85: The 8 table and the 9 table
All the tables practice →Lesson 85: Abacus times tables: 8 and 9
Level 7, Times Market. The biggest tables. The big friends do the work.
What your child does, card by card
The 8 table and the 9 table. Count by 8. Then count by 9. PlayType opens the lesson: “Now let's try a harder one.”
First a reminder (“8, 16, 24, 32, 40”): the beads build 8, 6, 16, 19, 14, 24, 22, 32, 30 and 40, ring by ring, while your child watches. Plus 8: two off, one ten on.
Try it: your child works out 10 × 8, with a green ring on the next bead to move.
Watch me: 9, 8, 18, 17, 27, 26, 36, 35 and 45 appear on the beads one move at a time, each bead ringed in green before it goes. Plus 9: one off, one ten on. Every time!
Try it puts a green ring on each next bead; your child works out 10 × 9.
A tiny practice with no ring: work out 6 × 8, 7 × 9, 8 × 8, 9 × 9 and 7 × 8, each round starting from its own number.
Then the beads hide and the sums 3 × 8, 4 × 9 and 6 × 9 are done in the head, the answer picked from 24, 36 and 54.
You're ready! You can count by 8 and by 9. That is every table!
What this lesson trains
About five minutes and 18 answers. Altogether the child makes 39 bead moves (11 with the top bead, 28 with bottom beads). The largest is 90: tens and ones. Then 3 quick looks in your head. 9 of the 15 sums need a big friend (“+8 = −2 +10”, “+8 = +3 −5 +10”, “+9 = +4 −5 +10” and “+9 = −1 +10”); the others use free beads.
It starts with doing: work out 10 × 8.
The sum sheet
The lower window shows the column as a child would write it on paper: one number under another, the current line in yellow, ticks on the lines done. The abacus carries the running total from line to line.
What PlayBuddy and PlayType say
PlayType: “Big friend off, one ten on.”
Stars
18 answers: 1 slip still gives three stars; up to 4, two stars.