Mind Castle — Lesson 103: Flash sums: more numbers
Flash practice: past ten →Lesson 103: Flash sums for kids: abacus mental math
Level 9, Mind Castle. First on the beads, then in your head: three or four numbers, one after another.
What your child does, card by card
Flash sums: more numbers. The numbers come one at a time. PlayBuddy opens the lesson: “Watch closely. The beads will hide!”
In Try it a green ring marks the next bead while your child works out the columns 3 + 5 + 1 and 2 + 5 + 1 - 3.
Flash sums in your head: the abacus is covered and the numbers appear one at a time, 1.5 seconds each (3 + 5 + 1, 1 + 2 + 5, 2 + 5 + 1 - 3 and 6 + 2 - 3 + 4); your child adds them in the head and picks the total from 5, 7, 8 and 9.
You're ready! Flash sums: see each number, add it in your head.
What this lesson trains
9 answers, roughly five minutes: 5 moves of the beads, 2 of them with the top bead and 3 with bottom beads. 9 is the top number here. Then 4 quick looks in your head.
The first thing your child does: work out the columns 3 + 5 + 1 and 2 + 5 + 1 - 3.
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: “Watch closely. The beads will hide!”
PlayBuddy: “Click Let's Begin, or press Enter!”
PlayType: “Now do it in your head.”
Stars
With no slips across the 9 answers your child earns three stars; 2 or fewer, two.