2
$9 + 5 =$
$14 - 9 =$
$9 + 7 =$
$16 - 9 =$
$9 + 9 =$
$18 - 9 =$
$9 + 3 =$
$12 - 9 =$
$9 + 1 =$
$10 - 9 =$
$9 + 2 =$
$11 - 9 =$
$9 - 9 =$
$11 + 9 =$
$11 + 6 =$
$5 + 8 =$
$6 + 7 =$
$4 + 16 =$
$13 - 7 =$
$10 - 1 =$
$8 + 7 =$
$2 + 17 =$
$5 + 5 =$
$19 - 9 =$
$9 + 6 =$
$15 - 9 =$
$9 + 4 =$
$13 - 9 =$
$9 + 8 =$
$17 - 9 =$
$4 + 9 =$
$13 - 3 =$
$4 + 7 =$
$12 + 3 =$
$7 + 7 =$
$4 + 8 =$
$14 - 9 + 2 =$
$16 - 5 - 9 =$
$17 - 9 - 1 =$
照样子在方框里填上合适的数

左边图表：
$3 + 9 = 12$，
$5 + 9 = 14$，
$7 + 9 = 16$，
$9 + 9 = 18$，
$2 + 9 = 11$，
$4 + 9 = 13$，
$6 + 9 = 15$，
$8 + 9 = 17$。
因此左边图表空缺的数字如下（按顺时针方向填入）：
$15$；$17$；$14$；
$11$；$13$；$16$；
$18$。
右边图表：
$13 - 9 = 4$，
$15 - 9 = 6$，
$17 - 9 = 8$，
$19 - 9 = 10$，
$18 - 9 = 9$，
$14 - 9 = 5$，
$12 - 9 = 3$，
$11 - 9 = 2$。
因此右边图表空缺的数字如下（按顺时针方向填入）：
$4$；$2$；$8$；
$10$；$3$；$5$；
$9$。