The teacher first arranges the colored beaded sticks representing the numbers in the formula into a long dragon (that is, colored snakes), and then counts them from left to right with the auxiliary tool "bridge". Every number 10 is replaced by a golden bead, so a * * replaces four golden beads (each golden bead represents 10), leaving less than 10. Count the replaced beads, (gold+gray) and the answer will come out, but when counting, you need 10 10, such as 10,20,30. . . Soon the children reported the answer 35.