Big Friends Bridge — Lesson 50: Minus 9 and minus 8 practice

What your child does, card by card

Minus 9 and minus 8 practice. Practice day! PlayBuddy opens the lesson: “Practice time. Let's get quicker and better.”

First a reminder (“Minus 9: 1 back. Minus 8: 2 back.”): the beads build 13, 3, 4, 13, 3 and 5, ring by ring, while your child watches. One ten goes off, both times.

Try it: your child works out 11 - 9 and 12 - 8, 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 10 - 9, 15 - 8, 17 - 9, 11 - 8, 16 - 9, 10 - 8, 18 - 9 and 17 - 8.

Copy me: the hand in the lower window shows 14, 7 and 19, one at a time, and your child makes the same number on the beads.

Then the beads hide and the sums 15 - 9, 16 - 8 and 11 - 9 are done in the head, the answer shown on the fingers.

You're ready! Minus 9 and minus 8, with the big friend.

What this lesson trains

16 answers, roughly five minutes: 27 moves of the beads, 2 of them with the top bead and 25 with bottom beads. The largest is 19: tens and ones. Then 3 quick looks in your head. 10 of the 10 sums need a big friend (“−9 = −10 +1” and “−8 = −10 +2”); the others use free beads.

The first thing your child does: work out 11 - 9 and 12 - 8.

Fingers and hands

Below the abacus the drawn hands show zero and 1, 2, 3, 4, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18 and 19 here, finger for bead: the left hand counts the tens, the right hand the ones.

−9 on the fingers: the left hand closes one finger for the ten and the right hand shows 1 more (−10 +1). −8 on the fingers: the left hand closes one finger for the ten and the right hand shows 2 more (−10 +2).

Copy me turns it round: 14, 7 and 19 appear on the hand first.

What PlayBuddy and PlayType say

PlayBuddy: “Taking ten is one too many. So one bead comes back!”

Stars

With 1 or fewer slips across the 16 answers your child earns three stars; 4 or fewer, two.