论文部分内容阅读
“150盏亮着的电灯,各有一个拉线开关控制,被按顺序编号为1,2,3,4,…,150。将编号为3的倍数的灯的拉线各拉一下,再将编号为5的倍数的拉线各拉一下,拉完后亮着的灯数为几?”这是一道考公因数和公倍数的思维数学题。今年暑假,才上完三年级的罗弋在做四年级的数学竞赛题集《培优新帮手》时遇到此题,算出答案“90”与标准答案“80”不符,妈妈陈群只当是儿子算错了。
“150 light lights, each with a pull switch control, are numbered sequentially 1, 2, 3, 4, ..., 150. The number of 3 times the number of lamp pull each pull a little, and then the number Pull the cable for the multiple of 5 pull a few, pull the number of lights after the light? ”This is a test of Gong Gong and common multiple thinking math problems. This summer, only finished the third grade Luo Yi in the fourth grade mathematics contest collection “Pei new helper,” encountered this problem, calculate the answer “90 ” and the standard answer “80 ” does not match, mother Chen Qun only when son is wrong.