Social Securitys benefit formula provides 90% of average indexed monthly earnings (AIME) below the first "bend point" of $791/month, 32% of AIME between the first and second bend points $791 to $4781/month, and 15% of AIME in excess of the second bend point up to the Ceiling cap of $113,700 in 2013. The low income bias of the benefit calculation means that lower paid worker receives a much higher percentage of his or her salary in benefit payments than higher paid workers. Indeed, a married low salaried worker can receive over 100% of their salary in benefits after retiring at the full retirement age. High-salaried workers receive 43% or less of their salary in benefits despite having paid into the "system" at the same rate—(see benefit calculations above.) To minimize the impact of Social Security taxes on low salaried workers the Earned Income Tax Credit" and the Child Care Tax Credit were passed, which largely refund the FICA and or SECA payments of low-salaried workers through the income tax system. By Congressional Budget Office (CBO) calculations the lowest income quintile (0-20%) and second quintile (21-40%) of households in the U.S. pay an average federal income tax of −9.3% and −2.6% of income and Social Security taxes of 8.3% and 7.9% of income respectively. By CBO calculations the household incomes in the first quintile and second quintile have an average total federal tax rate of 1.0% and 3.8% respectively. However, these groups also have by far the smallest percentage of American household incomes - the first quintile earns just 3.2% of all income, while the second quintile earns only 8.4% of all income. Higher-income retirees will have to pay income taxes on 85% of their Social Security benefits and 100% on all other retirement benefits they may have.

Question: How many dollars separate the first and second bend points?
Answer: 3990

Question: What two credits largely refunded the FICA and or SECA payments of low salaries workers?
Answer: Earned Income Tax Credit