If this was a real question, you’d have been able to research what a 70IQ looks like.
It’s mental retardation or borderline mental retardation, depending on which scale you use.
Schools give aptitude tests and someone with a 70IQ will be pretty apparent early on. They will have difficulties performing basic living tasks, like understanding a bus schedule, using a stove, filling out a form (or homework), or using a computer to research questions (like this one).
There are often behavior issues related with low IQs - cruelty, temper tantrums, emotions exceeding the situation, emotions lesser than the situation, violence, extreme happiness over mundane things, etc.
If a legit I.Q. test is administered at age 10 and the child scored a 70, he roughly has the same mental age as a 7 year old. At 15, a result of 70 is a mental age of around 10, which would be an obvious deficiency.