Big Friends Bridge — Lesson 52: Big friends: minus 5

What your child does, card by card

Big friends: minus 5. 5 and 5 make 10. PlayType opens the lesson: “Same trick, new friend.”

8 − 5 = 3: the top bead is on the bar. Send it up. The abacus makes 8, then clears. Here the hands lead: they show 8 and 3, and a moment later the beads copy each one. Above, “Start at 8” and “−5: the top bead = 3” take turns to glow. Its words: “Lesson 17: minus 5 is the top bead.”

12 − 5: no top bead on the bar. Only 2 ones. The top beads are outlined in yellow while the kids explain. The beads show 12 and go back to zero. The labels “Start at 12” and “− 5? No top bead” light up as each idea comes. “So take a ten!” Any bead or finger may be tapped afterwards.

Minus 5: one ten off, top bead down: 10 is 5 and 5. Taking a ten is 5 too many. The beads act out the friend rule while “−10: one ten”, “+5: the top bead comes down” and “−5 = −10 +5” light up; then your child must work out 12 - 5 and 14 - 5, a green ring on each bead in the friend's order.

Watch me: 12, 2, 7 and 2 appear on the beads one move at a time, each bead ringed in green before it goes. First no top bead: take a ten, top bead down. Then it is there: send it up.

Try it puts a green ring on each next bead; your child works out 10 - 5, 11 - 5 and 13 - 5.

A tiny practice with no ring: work out 14 - 5, 12 - 5, 17 - 5, 11 - 5 and 13 - 5, each round starting from its own number.

In Copy me the drawn hand holds up 7, 9 and 5 in turn, and your child copies each one in beads.

In your head: the abacus is covered and your child works out 12 - 5, 14 - 5 and 10 - 5, picking each answer from 5, 7 and 9.

You're ready! No top bead to send up? Take a ten, and bring the top bead down.

What this lesson trains

About five minutes and 16 answers. Altogether the child makes 24 bead moves (13 with the top bead, 11 with bottom beads). Up to 17, read and set from the left. Then 3 quick looks in your head. Friends do 9 of the 10 sums, by −5 = −10 +5.

Your child’s first moves: work out 10 - 5, 11 - 5 and 13 - 5.

Fingers and hands

Below the abacus the drawn hands show zero and 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 17 here, finger for bead: the left hand counts the tens, the right hand the ones.

−5 on the fingers: the left hand closes one finger for the ten and the right hand shows 5 more (−10 +5).

On “8 − 5 = 3” the hands move first and the beads follow, so your child sees that a finger and a bead move together: open a finger and a bead goes to the bar, close it and the bead goes back.

The fingers lead in Copy me (7, 9 and 5); the beads answer.

What PlayBuddy and PlayType say

PlayType: “To take away five, send the top bead back up.”

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

Stars

Three stars for up to 1 slip in 16 answers, two stars for up to 4.